TWI409170B - Anti - reflective multilayer laminated film - Google Patents

Anti - reflective multilayer laminated film Download PDF

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TWI409170B
TWI409170B TW094107329A TW94107329A TWI409170B TW I409170 B TWI409170 B TW I409170B TW 094107329 A TW094107329 A TW 094107329A TW 94107329 A TW94107329 A TW 94107329A TW I409170 B TWI409170 B TW I409170B
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film
thermoplastic resin
layer
melting point
uniaxially stretched
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TW094107329A
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TW200531830A (en
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Taro Oya
Masato Asai
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Teijin Dupont Films Japan Ltd
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11Anti-reflection coatings
    • G02B1/111Anti-reflection coatings using layers comprising organic materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/06Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/36Layered products comprising a layer of synthetic resin comprising polyesters
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00Layers arrangement
    • B32B2250/055 or more layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00Layers arrangement
    • B32B2250/24All layers being polymeric
    • B32B2250/244All polymers belonging to those covered by group B32B27/36
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00Coating on the layer surface
    • B32B2255/10Coating on the layer surface on synthetic resin layer or on natural or synthetic rubber layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00Coating on the layer surface
    • B32B2255/26Polymeric coating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2264/00Composition or properties of particles which form a particulate layer or are present as additives
    • B32B2264/10Inorganic particles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/40Properties of the layers or laminate having particular optical properties
    • B32B2307/406Bright, glossy, shiny surface
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/40Properties of the layers or laminate having particular optical properties
    • B32B2307/42Polarizing, birefringent, filtering
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/50Properties of the layers or laminate having particular mechanical properties
    • B32B2307/514Oriented
    • B32B2307/516Oriented mono-axially
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/70Other properties
    • B32B2307/704Crystalline
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00Electrical equipment
    • B32B2457/20Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202LCD, i.e. liquid crystal displays
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2323/00Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
    • C09K2323/03Viewing layer characterised by chemical composition
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528Polarisers
    • G02F1/133536Reflective polarizers
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528Polarisers
    • G02F1/133545Dielectric stack polarisers

Abstract

A laminated film obtained by carrying out anti-reflection processing on the surface of a reflection polarizing film. This laminated film comprising (A) a monoaxially oriented laminated film consisting of 501 or more alternating first layers made of a first thermoplastic resin having a positive stress optical coefficient and a thickness of 0.05 to 0.5 μm and second layers made of a second thermoplastic resin different from the first thermoplastic resin and having a thickness of 0.05 to 0.5 μm, and a low-reflectance layer formed on at least one side of the monoaxially oriented laminated film and having a reflectance of the surface measured from the input side of 3% or less.

Description

防反射多層層合薄膜Anti-reflection multilayer laminated film

本發明係有關將低液晶顯示層與高折射率層交替規則的配置,且藉由拉伸控制其折射率,以在特定之偏光成份的層間折射率差及各層之厚度,選擇性的將隨意的波長帶之光反射的單軸拉伸層合薄膜,與設置於其單面或雙面之防反射膜,使用於反射型偏光板之單軸拉伸多層層合薄膜以及液晶顯示用提升亮度之薄膜者。The present invention relates to a configuration in which a low liquid crystal display layer and a high refractive index layer are alternately arranged, and the refractive index thereof is controlled by stretching so that the interlayer refractive index difference and the thickness of each layer of a specific polarizing component are selectively arbitrary. a uniaxially stretched laminated film with light reflection in a wavelength band, an antireflection film provided on one or both sides thereof, a uniaxially stretched multilayer laminated film for use in a reflective polarizing plate, and a brightness enhancement for liquid crystal display The film.

多層層合薄膜係將低折射率層與高折射率層交替多層層合者,藉由層間之結構的光干擾,可使用於將特定波長之光選擇性的反射或穿透之光學干擾薄膜。又,如此之多層層合薄膜,將膜厚緩慢改變,將具有相異之反射尖峰的薄膜膠黏,可獲得與使用金屬之薄膜相同的高反射率,能使用為金屬光澤薄膜及反射鏡。進而,將如此之多層層合薄膜僅在一個方向拉伸,亦可使用為僅將特定之偏光成份反射的偏光反射薄膜;將其使用於液晶顯示等亦可做為液晶顯示等之提升亮度薄膜。The multilayer laminated film is obtained by alternately laminating a low refractive index layer and a high refractive index layer, and by optical interference of the structure between the layers, an optical interference film for selectively reflecting or penetrating light of a specific wavelength can be obtained. Further, in such a multilayer laminated film, the film thickness is gradually changed, and a film having a different reflection peak is adhered, and the same high reflectance as that of the metal film can be obtained, and a metallic gloss film and a mirror can be used. Further, such a multilayer laminated film may be stretched in only one direction, and a polarizing reflective film which reflects only a specific polarizing component may be used; and it may be used as a liquid crystal display or the like as a brightness enhancement film for liquid crystal display or the like. .

一般而言,在以具有層厚為0.05~0.5μm的不同折射率之層構成的多層光學薄膜中,藉由構成一方之層與構成他方之層的折射率差與膜厚及層合數,可發現將特定波長之光反射的所謂增反射現象。一般上,其反射波長以下述式(1)表示。In general, in a multilayer optical film comprising a layer having a different refractive index of a layer thickness of 0.05 to 0.5 μm, the refractive index difference and the film thickness and the number of laminations of the layer constituting the other layer are formed by the layer constituting the other layer. A so-called anti-reflection phenomenon that reflects light of a specific wavelength can be found. Generally, the reflection wavelength thereof is expressed by the following formula (1).

λ=2x((n1)x(d1)+(n2)x(d2))………(1)式中,λ為反射波長(nm),n1、n2為分別之層的折射率,d1、d2為分別之層的厚度(nm)。λ=2x((n1)x(d1)+(n2)x(d2)) (1) where λ is the reflection wavelength (nm), and n1 and n2 are the refractive indices of the respective layers, d1 D2 is the thickness (nm) of the respective layers.

如特開平04-268505號公報上之揭示,於一方之層使用具有正的應力光學係數之樹脂,藉由單軸拉伸可僅將雙折射中具有各向異性之特定偏光成份反射。使用此原理能設計例如將P偏光反射,使S偏光穿透之反射偏光薄膜。其時之適合的雙折射以下述式(2)表示。As disclosed in Japanese Laid-Open Patent Publication No. Hei 04-268505, a resin having a positive stress optical coefficient is used for one layer, and only a specific polarizing component having anisotropy in birefringence can be reflected by uniaxial stretching. Using this principle, it is possible to design, for example, a reflective polarizing film that reflects P-polarized light and allows S-polarized light to penetrate. The birefringence suitable at this time is represented by the following formula (2).

n1x>n2x、n1y=n2y………(2)式中,n1x、n2x為分別之層的拉伸方向之折射率,n1y、n2y為分別之層的垂直於拉伸方向之折射率。N1x>n2x, n1y=n2y (2) In the formula, n1x and n2x are the refractive indices of the respective layers in the stretching direction, and n1y and n2y are the refractive indices of the respective layers perpendicular to the stretching direction.

特表平9-506837號公報及WO-01/47711號公報上有高折射率層使用聚2,6-萘二羧酸乙二醇酯(以下亦簡稱為PEN)、低折射率層使用熱塑性彈性體之雙軸拉伸薄膜、及高折射率層使用PEN、低折射率層使用將異苯二甲酸30莫耳%共聚合之PEN的單軸拉伸多層層合薄膜之例示。此等薄膜係一方之層使用具有正的應力光學係數之樹脂、他方之層為應力光學係數非常小的樹脂;即,使用藉由拉伸顯現極小之雙折射的樹脂,僅將特定之偏光反射的反射偏光薄膜。如此的反射偏光薄膜可使用為液晶顯示之提升亮度薄膜。JP-A-H09-506837 and WO-01/47711 disclose the use of a polyethylene having a high refractive index layer of polyethylene-2,6-naphthalenedicarboxylate (hereinafter also referred to as PEN) and a low refractive index layer. The biaxially stretched film of the elastomer and the high refractive index layer are exemplified by the use of PEN and the low refractive index layer using a uniaxially stretched multilayer laminated film of PEN copolymerized with 30 mol% of isophthalic acid. The film of one of these films is a resin having a positive stress optical coefficient, and the other layer is a resin having a very small stress optical coefficient; that is, a resin which exhibits a birefringence by stretching to exhibit only a specific polarized light is reflected. Reflective polarizing film. Such a reflective polarizing film can be used as a brightness enhancement film for liquid crystal display.

一般而言,單軸拉伸多層層合薄膜之反射偏光薄膜使用為液晶顯示之提升亮度薄膜時,以包含拉伸方向與垂直於薄膜面之方向的兩方向,在平面平行的偏光成份之P偏光的可見光線反射率較接近於100%,在同平面垂直的偏光成份之S偏光較接近於0%,更適合。不過,已往之反射偏光薄膜,對上述平面之P偏光,雖可達成90%以上之反射率,但對S偏光具有約10~15%的反射率之故,藉此在液晶顯示內造成反射損耗,導致亮度降低。In general, when the reflective polarizing film of the uniaxially stretched multilayer laminated film is used as a brightness-enhancing film for liquid crystal display, the polarizing component parallel to the plane is included in both directions including the stretching direction and the direction perpendicular to the film surface. The visible light reflectance of polarized light is closer to 100%, and the S-polarized light of the polarizing component perpendicular to the same plane is closer to 0%, which is more suitable. However, in the past, the polarizing film has been reflected, and the P-polarized light of the above plane can achieve a reflectance of 90% or more, but has a reflectance of about 10 to 15% for the S-polarized light, thereby causing a reflection loss in the liquid crystal display. , resulting in reduced brightness.

如上所述,使用單軸拉伸多層層合薄膜之反射偏光薄膜,對拉伸方向與垂直方向為基準之平面S偏光之可見光線的光線反射率為10~15%左右。此主要為由於薄膜基材與空氣界面之折射率差的界面反射所致。減低如此之界面反射的方法,有防反射加工等。As described above, the reflected light-transmitting film of the uniaxially stretched multilayer laminated film is used, and the light reflectance of the visible light which is polarized to the plane S which is the direction of the stretching direction and the vertical direction is about 10 to 15%. This is mainly due to the interface reflection due to the difference in refractive index between the film substrate and the air interface. The method of reducing the reflection of such an interface is anti-reflection processing.

一般上顯示器等所使用之防反射塗佈,僅一層之塗佈並不能使遍及可見光全域之反射率降低,可使用基材/高折射率層/低折射率層之兩層塗佈,或基層/中折射率層/高折射率層/低折射率層等之三層塗佈等。In general, anti-reflective coating used for displays and the like, coating of only one layer does not reduce the reflectance throughout the entire visible light region, and two layers of the substrate/high refractive index layer/low refractive index layer can be used, or the base layer can be used. Three-layer coating of a medium refractive index layer/high refractive index layer/low refractive index layer or the like.

形成上述之防反射薄膜的方法有將溶液塗佈於薄膜一後經乾燥、層合之濕式塗佈法,與藉由濺鍍、蒸鍍等之乾式法;前者難以精確度優越之塗膜厚度重現而層合,後者之方法係採用精確度高的真空之故生產成本升高、生產性低,均有製造上的問題。The method for forming the antireflection film described above is a wet coating method in which a solution is applied to a film, followed by drying, lamination, and a dry method by sputtering, vapor deposition, etc.; the former is difficult to accurately coat the film. The thickness is reproduced and laminated, and the latter method uses a high-precision vacuum, so that the production cost is increased and the productivity is low, and there are manufacturing problems.

由於上述之理由,到目前為止並無適合使用於反射偏光薄膜表面之防反射加工。For the above reasons, there has been no anti-reflection processing suitable for use on the surface of a reflective polarizing film.

[發明之揭示][Disclosure of the Invention]

本發明之目的係解決已往多層層合薄膜所具有之上述問題,提供提升亮度效果跳躍似的增加、可使用於反射型偏光板之單軸拉伸多層層合薄膜。SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the conventional multilayer laminated film, and to provide a uniaxially stretched multilayer laminated film which can be used for a reflective polarizing plate in order to increase the brightness effect.

本發明之另一目的係提供由本發明之上述單軸拉伸多層層合薄膜所成的液晶顯示用提升亮度薄膜。Another object of the present invention is to provide a brightness-enhancing film for liquid crystal display formed by the above uniaxially stretched multilayer film of the present invention.

本發明之又一目的係提供構成本發明之上述單軸拉伸多層層合薄膜的單軸拉伸層合薄膜之製造方法。Still another object of the present invention is to provide a method for producing a uniaxially stretched laminated film constituting the above uniaxially stretched multilayer film of the present invention.

本發明之其他目的及優點可由下述之說明瞭解。Other objects and advantages of the invention will be apparent from the description which follows.

依本發明,本發明之上述目的及優點為,第一以(A)將由具有正的應力光學係數之第一熱塑性樹脂所成且厚度為0.05~0.5μm的第一層,及由與第一熱塑性樹脂相異之第二熱塑性樹脂所成且厚度為0.05~0.5μm的第二層,交替合計501層以上而存在之單軸拉伸層合薄膜,及在該單軸拉伸層合薄膜之至少單面上,具有由射入側測定表面之反射率為3%以下之低反射率層;(B)對含該單軸拉伸層合薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,平行的偏光成份之平均反射率在波長400~800nm的範圍為90%以上,且對含薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,垂直的偏光成份之平均反射率在波長400~800nm的範圍為10%以下;然後,(C)適合使用於反射型偏光板;為特徵,藉由單軸拉伸多層層合薄膜而達成。According to the present invention, the above objects and advantages of the present invention are as follows: (1) a first layer formed of a first thermoplastic resin having a positive stress optical coefficient and having a thickness of 0.05 to 0.5 μm, and a first layer a second layer of a thermoplastic resin different from the second thermoplastic resin and having a thickness of 0.05 to 0.5 μm, a uniaxially stretched laminated film in which 501 or more layers are alternately added, and a uniaxially stretched laminated film a low reflectance layer having a reflectance of 3% or less on the incident side of at least one surface; (B) a direction in which the uniaxially stretched laminated film is stretched and a direction perpendicular to the film surface In the two directions, the average reflectance of the parallel polarizing components is 90% or more in the wavelength range of 400 to 800 nm, and the vertical polarizing component is applied to the surface of the film containing the stretching direction and the direction perpendicular to the film surface. The average reflectance is 10% or less in the range of wavelength 400 to 800 nm; then, (C) is suitably used for a reflective polarizing plate; and it is characterized in that a multilayer laminated film is uniaxially stretched.

依本發明,本發明之上述目的及優點為,第二,提供由本發明之上述單軸拉伸多層層合薄膜所成的液晶顯示用提升亮度薄膜。According to the present invention, it is a second object of the present invention to provide a brightness-enhancing film for liquid crystal display comprising the uniaxially stretched multilayer film of the present invention.

依本發明,本發明之上述目的及優點為,第三以(A)將由具有正的應力光學係數之第一熱塑性樹脂所成且厚度為0.05~0.5μm的第一層,及由與第一熱塑性樹脂相異之第二熱塑性樹脂所成且厚度為0.05~0.5μm的第二層,交替合計501層以上而存在之單軸拉伸層合薄膜,及在該單軸拉伸層合薄膜之至少單面上具有折射率1.1~1.45的低折射率層;(B)對含該單軸拉伸層合薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,平行的偏光成份之平均反射率在波長400~800nm的範圍為90%以上,且對含薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,垂直的偏光成份之平均反射率在波長400~800nm的範圍為10%以下;然後,(C)適合使用於偏光板;為特徵,藉由單軸拉伸多層層合薄膜而達成。According to the present invention, the above object and advantage of the present invention is that the third layer (A) is made of a first thermoplastic resin having a positive stress optical coefficient and has a thickness of 0.05 to 0.5 μm, and is first and a second layer of a thermoplastic resin different from the second thermoplastic resin and having a thickness of 0.05 to 0.5 μm, a uniaxially stretched laminated film in which 501 or more layers are alternately added, and a uniaxially stretched laminated film a low refractive index layer having a refractive index of at least 1.1 to 1.45 on one side; (B) a polarizing component parallel to a direction including a stretching direction of the uniaxially stretched laminated film and a direction perpendicular to a direction of the film surface The average reflectance is 90% or more in the range of wavelength 400 to 800 nm, and the average reflectance of the vertical polarizing component is 400 to 800 nm in the direction of the film extending direction and the direction perpendicular to the film surface. The range is 10% or less; then, (C) is suitable for use in a polarizing plate; characteristically, it is achieved by uniaxially stretching a multilayer laminated film.

進而依本發明,本發明之上述目的及優點為,第四以由將熔點為260~270℃之第一熱塑性樹脂與比第一熱塑性樹脂之熔點低15~60℃的熔點之第二熱塑性樹脂交替層合501層以上形成薄片的第一步驟;將所得薄片在拉取方向或寬度方向之任一方向拉伸2~10倍的第二步驟;及將所得拉伸薄片在比第二熱塑性樹脂之熔點低10℃的溫度與比第一熱塑性樹脂之熔點低15℃的溫度之間的溫度進行熱處理之第三步驟所成,為特徵,藉由單軸拉伸多層層合薄膜之製造方法而達成。Further, according to the present invention, the above objects and advantages of the present invention are the fourth thermoplastic resin having a melting point of 260 to 270 ° C and a second thermoplastic resin having a melting point lower than the melting point of the first thermoplastic resin by 15 to 60 ° C. a first step of alternately laminating 501 layers or more to form a sheet; a second step of stretching the obtained sheet in either of a pulling direction or a width direction by 2 to 10 times; and subjecting the obtained stretched sheet to a second thermoplastic resin The third step of heat treatment at a temperature at which the melting point is 10 ° C lower than the temperature of the first thermoplastic resin by 15 ° C is characterized by the uniaxially stretched multilayer laminated film manufacturing method. Achieved.

[用以實施發明之最佳型態][The best form for implementing the invention]

就本發明詳細說明如下。The invention is described in detail below.

<單軸拉伸層合薄膜><uniaxially stretched laminated film>

本發明中,構成第一層之樹脂必要為具有正的應力雙折射(與應力光學係數同義)之第一熱塑性樹脂。具有正的應力雙折射之第一熱塑性樹脂有例如聚2,6-案二羧酸乙二醇酯(以下稱為2,6-PEN)及其同分異構物(例如1,4-、1,5-、2,7-及2,3-PEN)、聚對苯二甲酸烷基酯(例如聚對苯二甲酸乙二醇酯、聚對苯二甲酸丁二醇酯、及聚對苯二甲酸1,4-環己烷二亞甲基酯)聚異苯二甲酸乙二醇酯、聚醯亞胺(例如聚丙烯醯亞胺)、聚醚醯亞胺、聚烷烯聚合物(例如聚乙烯、聚丙烯、聚丁烯、聚異丁烯及聚(4-甲基)戊烯)、氟化聚合物(例如全氟烷氧基樹脂、聚四氟乙烯、氟化乙烯-丙烯共聚物、聚偏氟乙烯及聚氯三氟乙烯)、氯化聚合物(例如聚偏氯乙烯及聚氯乙烯)、聚碸、聚醚碸、聚丙烯腈、聚醯胺、矽氧樹脂、環氧樹脂、聚乙酸乙烯、聚醚醯胺、離子鍵聚合物、彈性體(例如聚丁二烯、聚異戊二烯及氯丁二烯橡膠)、以及聚胺基甲酸乙酯等等。In the present invention, the resin constituting the first layer is necessarily a first thermoplastic resin having positive stress birefringence (synonymous with stress optical coefficient). The first thermoplastic resin having positive stress birefringence is, for example, polyethylene-2,6-form dicarboxylate (hereinafter referred to as 2,6-PEN) and its isomers (for example, 1,4-, 1,5-, 2,7- and 2,3-PEN), polyalkylene terephthalates (eg polyethylene terephthalate, polybutylene terephthalate, and polypairs) 1,4-cyclohexanedimethylene phthalate) polyisophthalic acid ethylene glycol, polyimide (for example, polyacrylamide), polyether quinone, polyalkene polymer (eg polyethylene, polypropylene, polybutene, polyisobutylene and poly(4-methyl)pentene), fluorinated polymers (eg perfluoroalkoxy resins, polytetrafluoroethylene, fluorinated ethylene-propylene copolymerization) , polyvinylidene fluoride and polychlorotrifluoroethylene), chlorinated polymers (such as polyvinylidene chloride and polyvinyl chloride), polyfluorene, polyether oxime, polyacrylonitrile, polyamine, oxime, ring Oxygen resins, polyvinyl acetate, polyether amides, ionomers, elastomers (e.g., polybutadiene, polyisoprene, and chloroprene rubber), and polyurethanes and the like.

其中以應力雙折射大的聚2,6-萘二羧酸乙二醇酯(2,6-PEN)及其同分異構物(例如1,4-、1,5-、2,7-及2,3-PEN)、聚對苯二甲酸烷基酯(例如聚對苯二甲酸乙二醇酯、聚對苯二甲酸丁二醇酯、及聚對苯二甲酸1,4-環己烷二亞甲基酯)等較為適合。特別以2,6-、1,4-、1,5-、2,7-、及2,3-PEN更適合。Among them, polyethylene 2,6-naphthalene dicarboxylate (2,6-PEN) having a large stress birefringence and its isomers (for example, 1,4-, 1,5-, 2,7- And 2,3-PEN), polyalkylene terephthalate (such as polyethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate 1,4-cyclohexane Alkyl dimethylene ester) is suitable. In particular, 2,6-, 1,4-, 1,5-, 2,7-, and 2,3-PEN are more suitable.

還有,上述所謂聚2,6-萘二羧酸乙二酯係指以2,6-萘二羧酸乙二醇酯為主要重覆單位,例如2,6-萘二羧酸乙二醇酯為全重覆單位之80~100莫耳%,以佔90~100莫耳%更適合,包含均聚物及共聚物之意;其他之同分異構物亦相同。同樣的,所謂聚對苯二甲酸乙二醇酯係指以對苯二甲酸乙二醇酯為主要重覆單位,例如對苯二甲酸乙二醇酯為當重覆單位之80~100莫耳%,以佔90~100莫耳%更適合,包含均聚物及共聚物之意。Further, the above-mentioned polyethylene 2,6-naphthalenedicarboxylic acid ethylene glycol refers to ethylene-2,6-naphthalenedicarboxylate as a main repeating unit, for example, ethylene glycol 2,6-naphthalenedicarboxylate. The ester is 80-100 mol% of the total repeat unit, and is more suitable for 90-100 mol%, including the homopolymer and the copolymer; the other isomers are also the same. Similarly, polyethylene terephthalate refers to ethylene terephthalate as the main repeating unit, for example, ethylene terephthalate is 80 to 100 moles of the repeating unit. %, more preferably 90 to 100 mol%, including homopolymers and copolymers.

構成第二層之第二熱塑性樹脂,有做為第一熱塑性樹脂之上述列舉的熱塑性樹脂以外之例如無規之構聚苯乙烯、聚碳酸酯、聚甲基丙烯酸酯(例如聚甲基丙烯酸異丁酯、聚甲基丙烯酸丙酯、聚甲基丙烯酸乙酯、聚甲基丙烯酸甲酯)、聚丙烯酸酯(例如聚丙烯酸丁酯及聚丙烯酸甲酯)、間規之構聚苯乙烯(sPS)、間規主構聚-α-甲基苯乙烯、間規主構聚二氯苯乙烯,由此等隨意之聚苯乙烯所成的共聚物及摻合物、纖維素衍生物(例如乙基纖維素、乙酸纖維素、丙酸纖維素、乙酸丁酸纖維素、及硝基纖維素)等等。The second thermoplastic resin constituting the second layer, other than the above-exemplified thermoplastic resin as the first thermoplastic resin, such as random polystyrene, polycarbonate, polymethacrylate (for example, polymethacrylate) Ester, polypropyl methacrylate, polyethyl methacrylate, polymethyl methacrylate), polyacrylate (such as polybutyl acrylate and polymethyl acrylate), syndiotactic polystyrene (sPS), Syndiotactic main poly-α-methylstyrene, syndiotactic polydichlorostyrene, copolymers and blends of such random polystyrene, cellulose derivatives (such as ethylcellulose) , cellulose acetate, cellulose propionate, cellulose acetate butyrate, and nitrocellulose) and the like.

第二熱塑性樹脂必要與第一熱塑性樹脂相異,但不一定必要具有正的應力雙折射(與應力光學係數同義)。不過,使用具有正的應力雙折射率之第二熱塑性樹脂時,以低於第一熱塑性樹脂之熔點15~60℃較適合;其中從層間密著性之觀點而言,以使用低於第一熱塑性樹脂之特別適合的2,6-、1,4-、1,5-、2,7-或2,3-PEN之熔點15~60℃的共聚物更為適合。如此之共聚物有PEN之共聚物,例如2,6-、1,4-、1,5-、2,7-、及/或2,3-萘二羧酸或其酯與,(a)對苯二甲酸或其酯,(b)異苯二甲酸或其酯,(c)苯二甲酸或其酯,(d)烷二醇,(e)環烷二醇,例如環己烷二甲酸,(f)烷二羧酸及/或(g)環烷二羧酸,例如環己烷二羧酸之共聚物;聚苯苯二甲酸烷基酯之共聚物,例如對苯二甲酸或其酯與,(a)萘二羧酸或其酯,(b)異苯二甲酸或其酯,(c)苯二甲酸或其酯,(d)烷二醇,(e)環烷二醇,例如環己烷二甲酸,(f)烷二羧酸及/或(g)環烷二羧酸,例如環己烷二羧酸之共聚物;苯乙烯共聚物,例如苯乙烯-丁二烯共聚物及苯乙烯-丙烯腈共聚物;以及4,4’-二安息香酸與乙二醇之共聚物等等。The second thermoplastic resin must be different from the first thermoplastic resin, but does not necessarily have to have positive stress birefringence (synonymous with the stress optical coefficient). However, when a second thermoplastic resin having a positive stress birefringence is used, it is preferably 15 to 60 ° C lower than the melting point of the first thermoplastic resin; wherein, from the viewpoint of interlayer adhesion, the use is lower than the first A particularly suitable copolymer of 2,6-, 1,4-, 1,5-, 2,7- or 2,3-PEN having a melting point of 15 to 60 ° C is more suitable. Such copolymers are copolymers of PEN, such as 2,6-, 1,4-, 1,5-, 2,7-, and/or 2,3-naphthalenedicarboxylic acid or esters thereof, (a) Terephthalic acid or its ester, (b) isophthalic acid or its ester, (c) phthalic acid or its ester, (d) alkanediol, (e) cycloalkanediol, such as cyclohexanedicarboxylic acid , (f) alkanedicarboxylic acid and / or (g) a cycloalkanedicarboxylic acid, such as a copolymer of cyclohexanedicarboxylic acid; a copolymer of a polyalkylene terephthalate, such as terephthalic acid or And (a) naphthalene dicarboxylic acid or its ester, (b) isophthalic acid or its ester, (c) phthalic acid or its ester, (d) alkanediol, (e) cycloalkanediol, For example, cyclohexanedicarboxylic acid, (f) alkanedicarboxylic acid and/or (g) a cycloalkanedicarboxylic acid such as a copolymer of cyclohexanedicarboxylic acid; a styrene copolymer such as styrene-butadiene copolymer And a styrene-acrylonitrile copolymer; and a copolymer of 4,4'-dibenzoic acid and ethylene glycol, and the like.

就本發明中單軸拉伸層合薄膜之適合例更詳細說明如下。A suitable example of the uniaxially stretched laminated film of the present invention will be described in more detail below.

在本發明的最適合之例中,構成第一層之第一熱塑性樹脂為由以2,6-萘二羧酸乙二醇酯成份為主要重覆單位所成之聚酯。適合的是,能維持比構成後述之第二層的聚酯高之熔點的均聚2,6-萘二羧酸乙二醇酯或重覆單位之95莫耳%以為由2,6-萘二羧酸乙二醇酯成份所成之共聚2,6-萘二羧酸乙二醇酯。2,6-萘二羧酸乙二醇酯成份之莫耳數低於重覆單位的95莫耳%時,熔點降低不能獲得與構成後述之第二層的聚酯之熔點差,結果不能賦予拉伸層合薄膜充分之折射率差。其中以能維持高熔點之均聚2,6-萘二羧酸乙二醇酯較為適合。2,6-萘二羧酸乙二醇酯成份以外之共聚合成份,適合的有異苯二甲、2,7-萘二羧酸等其他之芳香族羧酸;己二酸、壬二酸、癸二酸、癸烷二羧酸等脂肪族二羧酸;環己烷二羧酸等脂環族二羧酸等酸成份、丁烷二醇、己烷二醇等脂肪族二醇;環己烷二甲醇等脂環族二醇等二醇成份。In a most suitable embodiment of the present invention, the first thermoplastic resin constituting the first layer is a polyester obtained by using a 2,6-naphthalenedicarboxylate component as a main repeating unit. It is suitable that the homopolymerized ethylene 2,6-naphthalenedicarboxylate or the 95 mol% of the repeating unit can be maintained at a higher melting point than the polyester constituting the second layer described later as 2,6-naphthalene The ethylene glycol dicarboxylate component is copolymerized with ethylene glycol 2,6-naphthalene dicarboxylate. When the molar amount of the ethylene compound of 2,6-naphthalenedicarboxylate is less than 95% by mole of the repeating unit, the melting point is lowered, and the difference in melting point from the polyester constituting the second layer described later cannot be obtained, and as a result, it cannot be imparted. The stretched laminate film has a sufficient refractive index difference. Among them, homopolymerized 2,6-naphthalenedicarboxylate which can maintain a high melting point is suitable. a copolymerization component other than the ethylene glycol 2,6-naphthalene dicarboxylate component, and other aromatic carboxylic acids such as isophthalic acid and 2,7-naphthalenedicarboxylic acid; adipic acid and sebacic acid; An aliphatic dicarboxylic acid such as azelaic acid or a decane dicarboxylic acid; an acid component such as an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; an aliphatic diol such as butanediol or hexanediol; A diol component such as an alicyclic diol such as hexane dimethanol.

可是,構成第一層之樹脂的熔點為260~270℃之範圍,以能增大與構成後述之第二層的樹脂之熔點差為佳。構成第一層之樹脂的熔點低於下限時,與構成第二層之樹脂的熔點差減小,結果難以賦予所得單軸拉伸薄膜充分之折射率差。還有,均聚2,6-萘二羧酸乙二醇酯之熔點為267℃左右。However, the melting point of the resin constituting the first layer is in the range of 260 to 270 ° C, and it is preferable to increase the difference in melting point of the resin constituting the second layer to be described later. When the melting point of the resin constituting the first layer is less than the lower limit, the difference in melting point from the resin constituting the second layer is small, and as a result, it is difficult to impart a sufficient refractive index difference to the obtained uniaxially stretched film. Further, the homopolymerized ethylene glycol 2,6-naphthalenedicarboxylate has a melting point of about 267 °C.

本發明的最適合之例中,構成第二層之第二熱塑性樹脂係由熔點為210~255℃之主要重覆單位的2,6-萘二羧酸乙二醇酯成份所成的聚酯。尤其從單軸拉伸中製膜性之觀點而言,以結晶性聚酯較適合。又,能使熔點比構成上述之第一層的聚酯低之重覆單位的40~98.5莫耳%,以75~97莫耳%更適合,為由2,6-萘二羧酸乙二醇酯成份所成;1.5~60莫耳%,以3~25莫耳%更適合,為由其以外之共聚合成份,例如對苯二甲酸乙二醇酯及/或異對苯二甲酸乙二醇酯所成之共2,6-萘二羧酸乙二醇酯。2,6-萘二羧酸乙二醇酯成份之莫耳數低於重覆單位的75莫耳%而共聚合成份之莫耳數超過25莫耳%時,實質上聚合物為非晶質,於單軸拉伸之製膜性下降,且與構成上述之第一層的聚酯之組成大為不同,層間之密著性容易降低。另一方面,2,6-萘二羧酸乙二醇酯成份之莫耳數超過重覆單位的97莫耳%而共聚合成份之莫耳數低於3莫耳%時,與構成上述之第一層的聚酯之熔點差減小,結果難以賦予拉伸層合薄膜充分之反射率。2,6-萘二羧酸乙二醇酯成份以外之共聚合成份,適合的有異苯二甲酸、2,7-萘二羧酸等其他之芳香族羧酸;己二酸、壬二酸、癸二酸、癸烷二羧酸等脂肪族二羧酸;環己烷二羧酸等脂環族二羧酸等酸成份、丁烷二醇、己烷二醇等脂肪族二醇;環己烷二甲醇等脂環族二醇等二醇成份。其中尤其從比較上維持拉伸性同時容易使熔點降低而言,以對苯二甲酸或異苯二甲酸為佳。In a most suitable embodiment of the present invention, the second thermoplastic resin constituting the second layer is a polyester composed of a main repeating unit of ethylene glycol 2,6-naphthalene dicarboxylate having a melting point of 210 to 255 °C. . In particular, from the viewpoint of film formability in uniaxial stretching, a crystalline polyester is suitable. Further, it is possible to make the melting point 40 to 98.5 mol% lower than the repeating unit constituting the first layer of the polyester, and more preferably 75 to 97 mol%, which is 2,6-naphthalenedicarboxylic acid ethylene Alcohol ester component; 1.5~60 mol%, more suitable for 3~25 mol%, other than copolymerization components such as ethylene terephthalate and / or isophthalic acid B A total of 2,6-naphthalenedicarboxylate ethylene glycol ester. When the molar amount of the ethylene glycol of 2,6-naphthalenedicarboxylate is less than 75 mol% of the repeating unit and the molar number of the copolymerized component exceeds 25 mol%, the polymer is substantially amorphous. The film forming property of the uniaxial stretching is lowered, and the composition of the polyester constituting the first layer described above is greatly different, and the adhesion between the layers is liable to lower. On the other hand, when the molar amount of the ethylene glycol of 2,6-naphthalenedicarboxylate exceeds 97 mol% of the repeating unit and the molar number of the copolymerized component is less than 3 mol%, The difference in melting point of the polyester of the first layer is reduced, and as a result, it is difficult to impart sufficient reflectance to the stretched laminated film. a copolymerization component other than the ethylene glycol 2,6-naphthalene dicarboxylate component, and other aromatic carboxylic acids such as isophthalic acid and 2,7-naphthalene dicarboxylic acid; adipic acid and sebacic acid; An aliphatic dicarboxylic acid such as azelaic acid or a decane dicarboxylic acid; an acid component such as an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; an aliphatic diol such as butanediol or hexanediol; A diol component such as an alicyclic diol such as hexane dimethanol. Among them, terephthalic acid or isophthalic acid is preferred, in particular, from the viewpoint of maintaining the stretchability in comparison and easily lowering the melting point.

可是,構成第二層之第二熱塑性樹脂的熔點為210~255℃之範圍,以能增大與構成上述第一層之第一熱塑性樹脂的熔點差為佳。構成第二層之第二熱塑性樹脂的熔點高於上限時,與構成第一層之第一熱塑性樹脂的熔點差減小,結果難以賦予所得拉伸層合薄膜充分之折射率差。另一方面,構成第二層之第二熱塑性樹脂的熔點低於下限時,與構成第一層之第一熱塑性樹脂的組成大為改變,難以賦予所得單軸拉伸層合薄膜充分之層間的密著性。還有,構成第二層之第二熱塑性樹脂的熔點,沒必要自形成薄膜前之階段就低,在拉伸處理後降低即可。例如,準備均聚2,6-萘二羧酸乙二醇酯與其以外之其他的聚酯,將此等熔融混煉,其時進行酯交換者亦可。However, the melting point of the second thermoplastic resin constituting the second layer is in the range of 210 to 255 ° C, and it is preferable to increase the difference in melting point from the first thermoplastic resin constituting the first layer. When the melting point of the second thermoplastic resin constituting the second layer is higher than the upper limit, the difference in melting point from the first thermoplastic resin constituting the first layer is decreased, and as a result, it is difficult to impart a sufficient refractive index difference to the obtained stretched laminated film. On the other hand, when the melting point of the second thermoplastic resin constituting the second layer is less than the lower limit, the composition of the first thermoplastic resin constituting the first layer is largely changed, and it is difficult to impart sufficient interlayer between the obtained uniaxially stretched laminated films. Adhesiveness. Further, the melting point of the second thermoplastic resin constituting the second layer is not necessarily lowered from the stage before the film formation, and may be lowered after the stretching treatment. For example, it is preferable to prepare a homopoly 2,6-naphthalenedicarboxylate and other polyesters, and to melt and knead them, and it is also possible to carry out transesterification.

第一層及第二層為藉由層間之光干擾,選擇性將光反射,第一層及第二層中各別一層之厚度為0.05~0.5μm的範圍。多層光學薄膜之反射特性,以層數、折射率差、層之厚度而決定。本發明中單軸拉伸層合薄膜所示之反射波長帶,自可見光區域至近紅外線區域之故必要在上述層厚的範圍。層厚超過0.5μm時反射帶域成為紅外線區域,不能獲得適合之反射偏光薄膜。另一方面低於0.05μm時,光射光之反射帶域成為紫外線區域,不能獲得實質性能。The first layer and the second layer selectively reflect light by light interference between the layers, and the thickness of each of the first layer and the second layer is in the range of 0.05 to 0.5 μm. The reflection characteristics of the multilayer optical film are determined by the number of layers, the difference in refractive index, and the thickness of the layer. In the present invention, the reflection wavelength band shown by the uniaxially stretched laminated film is required to be in the range of the above layer thickness from the visible light region to the near-infrared region. When the layer thickness exceeds 0.5 μm, the reflection band becomes an infrared region, and a suitable reflective polarizing film cannot be obtained. On the other hand, when it is less than 0.05 μm, the reflection band of the light-emitting light becomes an ultraviolet region, and substantial energy cannot be obtained.

本發明中之單軸拉伸層合薄膜,層合數必要為至少501層。層數低於501層時,在波長400~800nm之範圍不能滿足以上述為目的的光學特性。層合數之上限,從生產性及薄膜之處理性等觀點而言,以2001層為最高較適合。In the uniaxially stretched laminated film of the present invention, the number of laminations is required to be at least 501 layers. When the number of layers is less than 501 layers, the optical characteristics for the above purpose cannot be satisfied in the range of wavelengths of 400 to 800 nm. The upper limit of the number of lamellas is the most suitable for the 2001 layer from the viewpoints of productivity and film rationality.

此單軸拉伸層合薄膜中,對第一層之平均厚度,第二層的平均厚度之比,以0.5~5.0為宜,以1.0~4.0更適合,以1.5~3.5最理想。藉由改變第一層與第二層之厚度比可維持層間的密著性;又,不改變使用之樹脂能調整單軸拉伸層合薄膜的機械特性。對第一層平均厚度,第二層平均厚度之比低於0.5時,在單軸拉伸層合薄膜之拉伸方向容易撕裂;另一方面超過5.0時,經處理於定向緩和之差異單軸拉伸層合薄膜的厚度之改變容易增大。In the uniaxially stretched laminated film, the ratio of the average thickness of the first layer to the average thickness of the second layer is preferably 0.5 to 5.0, more preferably 1.0 to 4.0, and most preferably 1.5 to 3.5. The adhesion between the layers can be maintained by changing the thickness ratio of the first layer to the second layer; further, the mechanical properties of the uniaxially stretched laminated film can be adjusted without changing the resin used. When the ratio of the average thickness of the first layer to the average thickness of the second layer is less than 0.5, the tensile direction of the uniaxially stretched laminated film is easily torn; on the other hand, when it exceeds 5.0, the difference between the treatment and the directional relaxation is single. The change in the thickness of the axially stretched laminated film is apt to increase.

又,光學多層薄膜係依上述式(1),藉由折射率、層數、層的厚度而決定反射之波長,層合之第一層及第二層分別為一定之厚度時,僅能反射特定之波長。Further, in the optical multilayer film, the wavelength of reflection is determined by the refractive index, the number of layers, and the thickness of the layer according to the above formula (1). When the first layer and the second layer which are laminated are each a certain thickness, only the reflection can be performed. Specific wavelength.

本發明之單軸拉伸層合薄膜中,第一層及第二層分別的最大厚度與最小厚度之比,以1.5~5.0為宜,以2.0~4.0更適合,以2.5~3.5最理想。第一層及第二層為階段式改變亦可,連續式改變亦可。以如此層合之第一層及第二層的分別改變,能將更廣濶波長區域之光反射。第一層及第二層分別的最大厚度與最小厚度之比低於1.5時,難以覆蓋400~800nm之波長區域的範圍之做為上述目的的反射特性。另一方面,超過5.0時,反射帶域過於廣闊反射率降低,難以獲得上述目的之反射特性。又,此時層合結構為階段式或連續式改變之多層結構的表層,或於內部存在一層以上的0.5μm以上之層亦可。In the uniaxially stretched laminated film of the present invention, the ratio of the maximum thickness to the minimum thickness of the first layer and the second layer is preferably 1.5 to 5.0, more preferably 2.0 to 4.0, and most preferably 2.5 to 3.5. The first layer and the second layer may be changed in stages, and continuous changes may also be made. With the respective changes of the first layer and the second layer thus laminated, light of a wider wavelength region can be reflected. When the ratio of the maximum thickness to the minimum thickness of the first layer and the second layer is less than 1.5, it is difficult to cover the range of the wavelength region of 400 to 800 nm as the reflection characteristic for the above purpose. On the other hand, when it exceeds 5.0, the reflectance band is too broad and the reflectance is lowered, and it is difficult to obtain the reflection characteristics of the above object. Further, in this case, the laminated structure may be a surface layer of a multilayer structure in which the stepwise or continuous change is performed, or a layer of 0.5 μm or more or more may be present inside.

本發明中單軸拉伸層合薄膜,對含該單軸拉伸薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之平面,平行的偏光成份之平均反射率在波長400~800的範圍為90%以上,以95%以上更適合,以98%以上最理想;對同平面垂直的偏光成份之平均反射率在波長400~800的範圍為10%以下,以5%以下較適合,以3%以下更佳,以1%以下最理想。對含單軸拉伸薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之平面,平行的偏光成份之平均反射率在波長400~800nm的範圍低於90%時,做為反射型偏光薄膜之偏光反射性能不足,做為液晶顯示等之提升亮度薄膜不能顯現充分的性能。又,對同平面垂直的偏光成份之平均反射率超過10%時,在波長400~800nm之範圍,做為反射型偏光薄膜的偏光穿透率降低之故,做為液晶顯示等之提升亮度薄膜的性能劣化。In the uniaxially stretched laminated film of the present invention, the average reflectance of the polarizing component parallel to the plane containing the uniaxially stretched film and the direction perpendicular to the direction of the film surface is at a wavelength of 400 to 800. The range is more than 90%, more suitable for 95% or more, and more preferably 98% or more; the average reflectance of the polarizing component perpendicular to the same plane is 10% or less in the range of wavelength 400 to 800, and is preferably 5% or less. It is preferably 3% or less, and most preferably 1% or less. For the plane containing the uniaxially stretched film and the direction perpendicular to the direction of the film surface, the average reflectance of the parallel polarized components is less than 90% in the wavelength range of 400 to 800 nm, and is used as the reflective polarized light. The polarized reflection performance of the film is insufficient, and the enhanced brightness film such as a liquid crystal display cannot exhibit sufficient performance. Further, when the average reflectance of the polarizing component perpendicular to the same plane exceeds 10%, the polarized light transmittance of the reflective polarizing film is lowered in the range of 400 to 800 nm, and it is used as a brightness enhancement film for liquid crystal display or the like. The performance is degraded.

此單軸拉伸層合薄膜中,對含單軸拉伸薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之平面,平行的偏光成份之於波長400~800nm的範圍,最大反射率與最小反射率之差為10%以內,且對同平面垂直的偏光成份之於波長400~800nm的範圍,最大反射率與最小反射率之差以在10%以內較適合。上述偏光成份的最大反射率與最小反射率之差超過10%時,產生反射或穿透之光色相的任一種之故,使用於液晶顯示等有產生問題之情況。In the uniaxially stretched laminated film, the parallel polarized component is in the range of 400 to 800 nm in the plane of the uniaxially stretched film and the plane perpendicular to the direction of the film surface, and the maximum reflectance is obtained. The difference between the minimum reflectance and the minimum reflectance is 10%, and the polarization component perpendicular to the same plane is in the range of 400 to 800 nm, and the difference between the maximum reflectance and the minimum reflectance is preferably within 10%. When the difference between the maximum reflectance and the minimum reflectance of the polarizing component exceeds 10%, any one of the light hue of reflection or penetration is generated, which may cause problems in liquid crystal display or the like.

圖1為表示本發明之單軸拉伸層合薄膜的反射率曲線之一例。P偏光為在含薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之平面的平行之偏光成份,S偏光為在含薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之平面的垂直之偏光成份。Fig. 1 is a view showing an example of a reflectance curve of a uniaxially stretched laminated film of the present invention. P-polarized light is a parallel polarizing component in a plane containing both the stretching direction of the film and the direction perpendicular to the film surface, and the S-polarized light is a plane in both directions of stretching of the film and directions perpendicular to the film surface. Vertical polarizing component.

本發明之單軸拉伸層合薄膜中,層合多層結構之方法沒有特別的限制,例如有將做為第一層之聚酯支化為251層,將做為第二層之聚酯支化為250層,然後將第一層與第二層交替層合,採用使其流路連續改變1~3倍之多層進料單元裝置的方法;藉由多層進料單元裝置,將201層之均勻層層合,將其層合的流動體更以1.0:1.3:2.0之比,垂直於層合之面支化為3後再層合為601層的方面。將此等兩者組合使用亦可。In the uniaxially stretched laminated film of the present invention, the method of laminating the multilayer structure is not particularly limited, and for example, the polyester as the first layer is branched into 251 layers, and the polyester layer as the second layer is used. Divided into 250 layers, and then alternately laminating the first layer and the second layer, using a method of continuously changing the flow path by 1 to 3 times the multi-layer feeding unit device; by means of a multi-layer feeding unit device, 201 layers The uniform layer is laminated, and the laminated fluid is further laminated to 601 layers perpendicular to the lamination surface at a ratio of 1.0:1.3:2.0. It is also possible to use these two in combination.

本發明之單軸拉伸層合薄膜,係將上述之第一層及第二層交替至少合計501層層合者。還有,本發明之單軸拉伸層合薄膜,如上所述,為滿足目的之做為反射偏光薄膜的光學特性,於單軸方向拉伸。此時之拉伸方向為縱方向,於橫方向拉伸亦可。又,在滿足光學特性的範圍賦予多段拉伸亦可。又,拉伸方法可使用藉由棒狀加熱器之加熱拉伸、滾筒加熱拉伸、拉幅器拉伸等眾所周知的拉伸方法,從藉由與滾筒接觸減低缺陷及拉伸速度之觀點而言,以拉幅器拉伸較為適合。還有,所謂單軸拉伸,並非指在垂直於單軸拉伸方向的方向完全不拉伸之意,包含於直角方向例如1.2倍以下,以1.1倍以下更適合的拉伸之意。In the uniaxially stretched laminated film of the present invention, at least 501 layers of the first layer and the second layer are alternately laminated. Further, as described above, the uniaxially stretched laminated film of the present invention is stretched in the uniaxial direction for the purpose of satisfying the optical characteristics of the reflective polarizing film. In this case, the stretching direction is the longitudinal direction and the stretching may be performed in the transverse direction. Moreover, it is also possible to provide a plurality of stages of stretching in a range in which optical characteristics are satisfied. Further, as the stretching method, a well-known stretching method such as heating by a rod heater, drum heating stretching, tenter stretching, or the like can be used, from the viewpoint of reducing defects and stretching speed by contact with the roller. In other words, it is more suitable to stretch with a tenter. Further, the term "uniaxial stretching" does not mean that the film is not stretched completely in the direction perpendicular to the uniaxial stretching direction, and is included in the direction perpendicular to the direction of, for example, 1.2 times or less, and more preferably 1.1 times or less.

尤其從確保層間之密著性及拉伸加工之製膜性而言,本發明之單軸拉伸層合薄膜的第一層及第二層同時由顯示正的應力光學係數之結晶性樹脂所成,且第二層之第二熱塑性樹脂於拉伸後,至少一部份熔融緩和定向極為適合。以DSC(差示掃描熱量計)測定如此而得之單軸拉伸層合薄膜有兩個以上之熔點存在,且此等之熔點有5℃以上之差異,甚為適合。於此比測定高之熔點為顯示高折射率之第一層的第一熱塑性樹脂,較低之熔點為顯示低反射率之第二層的第二熱塑性樹脂。又,拉伸後第二層的至少一部份熔融之故,以DSC測定之結晶化尖峰存在於150~220℃的範圍,非常適合。結晶化尖峰為150℃以下時,在薄膜拉伸之際,一方之層激烈結晶化使製膜時的製膜性降低,膜質之均勻性容易下降,結果有產生色相之斑點等的情況。另一方面,結晶化尖峰為220℃以上時,在後述的製造方法中以熱固定處理將第二層熔融之際同引起結晶化,難以顯現充分之折射率差。In particular, from the viewpoint of ensuring the adhesion between the layers and the film forming property of the stretching process, the first layer and the second layer of the uniaxially stretched laminated film of the present invention are simultaneously composed of a crystalline resin exhibiting a positive stress optical coefficient. After the second thermoplastic resin of the second layer is stretched, at least a portion of the melt-relaxed orientation is extremely suitable. It is determined by DSC (differential scanning calorimeter) that the uniaxially stretched laminated film thus obtained has two or more melting points, and such a melting point has a difference of 5 ° C or more, which is suitable. Here, the first thermoplastic resin having a higher melting point is the first layer exhibiting a high refractive index, and the lower melting point is a second thermoplastic resin exhibiting a second layer having a low reflectance. Further, since at least a part of the second layer after the stretching is melted, the crystallization peak measured by DSC exists in the range of 150 to 220 ° C, which is very suitable. When the crystallization peak is 150° C. or lower, the film is strongly crystallized when the film is stretched, and the film formability at the time of film formation is lowered, and the uniformity of the film quality is likely to be lowered. As a result, a hue of the hue or the like may occur. On the other hand, when the crystallization peak is 220° C. or more, in the production method described later, the second layer is melted by the heat setting treatment to cause crystallization, and it is difficult to develop a sufficient refractive index difference.

如上所述,本發明之單軸拉伸層合薄膜藉由將同時顯示結晶性之第一層的第一熱塑性樹脂與第二層之第二熱塑性樹脂拉伸,可得均勻之膜質的薄膜;且於拉伸步驟後將第二層熔融,能提高層間密著性同時提升反射性能。因此,本發明之單軸拉伸層合薄膜中,藉由DSC觀測到結晶尖峰存在於150~220℃,熔點差為5℃以上之不同的兩個以上之熔融尖峰的單軸拉伸層合薄膜,極為適合又,本發明之單軸拉伸層合薄膜,拉伸處理之方向的斷裂強度分別以100MPa較適合。斷裂強度低於100MPa時,單軸拉伸層合薄膜於加工之際的處理性降低,製成產品時之耐久性下降。又,斷裂強度為100MPa以上時,薄膜強硬有提升捲取性之優點。適合之斷裂強度,縱方向為150MPa以上,以200MPa以上更佳;橫方向為150MPa以上,以200MPa以上更佳。又,縱方向與橫方向之強度比,為3以下時具備充分的耐撕裂性之故較為適合。尤其縱方向與橫方向之強度比為2以下時,更能提升耐撕裂性,甚為適合。斷裂強度之上限沒有特別的限制,從維持拉伸步驟之穩定性的觀點而言,以最高為500MPa較適合。As described above, the uniaxially stretched laminated film of the present invention can obtain a uniform film of the film by stretching the first thermoplastic resin which simultaneously exhibits the first layer of crystallinity and the second thermoplastic resin of the second layer; And melting the second layer after the stretching step can improve interlayer adhesion while improving reflection performance. Therefore, in the uniaxially stretched laminated film of the present invention, uniaxially stretched lamination of two or more melting peaks having crystal melting peaks present at 150 to 220 ° C and melting point difference of 5 ° C or more is observed by DSC. The film is extremely suitable. Further, in the uniaxially stretched laminated film of the present invention, the breaking strength in the direction of the stretching treatment is preferably 100 MPa. When the breaking strength is less than 100 MPa, the handleability of the uniaxially stretched laminated film at the time of processing is lowered, and the durability at the time of product formation is lowered. Further, when the breaking strength is 100 MPa or more, the film is tough and has the advantage of improving the take-up property. A suitable breaking strength is 150 MPa or more in the longitudinal direction, more preferably 200 MPa or more, and 150 MPa or more in the transverse direction, and more preferably 200 MPa or more. Further, when the strength ratio in the longitudinal direction and the lateral direction is 3 or less, it is suitable for having sufficient tear resistance. In particular, when the strength ratio in the longitudinal direction to the lateral direction is 2 or less, the tear resistance is further improved, which is suitable. The upper limit of the breaking strength is not particularly limited, and from the viewpoint of maintaining the stability of the stretching step, it is preferably at most 500 MPa.

又,本發明之單軸拉伸層合薄膜之特徵係,第一熱塑性樹脂為聚2,6-萘二羧酸乙二醇酯時,熱尺寸穩定性甚高,特別在加工製程中必要160℃以上之高溫時能充分對應。本薄膜之拉伸處理方向(製膜方向及寬度方向之任一種)的150℃30分鐘處理時之熱收縮率以5.0%以下較為適合,以1.5%以下更佳,以1.0%以下最理想。又,本發明之單軸拉伸層合薄膜於200℃10分鐘處理時之製膜方向及寬度方向的任一種之熱收縮率以3.0%以下較適合,以20%以下更佳,以1.5%以下最理想。Moreover, the uniaxially stretched laminated film of the present invention is characterized in that the first thermoplastic resin is polyethylene-2,6-naphthalenedicarboxylate, and the thermal dimensional stability is very high, especially in the processing process. When the temperature is higher than °C, it can fully correspond. The heat shrinkage ratio at the time of the treatment at 150 ° C for 30 minutes in the stretching treatment direction (any one of the film forming direction and the width direction) of the film is preferably 5.0% or less, more preferably 1.5% or less, and most preferably 1.0% or less. Further, in the uniaxially stretched laminated film of the present invention, the heat shrinkage ratio in any one of the film forming direction and the width direction at the time of treatment at 200 ° C for 10 minutes is preferably 3.0% or less, more preferably 20% or less, and 1.5% or less. The following is ideal.

又,本發明之單軸拉伸層合薄膜中,構成第一層及第二層之樹脂,如上所述以同時為結晶性樹脂較適合。構成第一層及第二層之樹脂同時為結晶性樹脂時,拉伸等處理不會有不均勻之情況,結果能使薄膜之厚斑減小。厚斑之範圍,以下述式(3)所示之厚度變動率為10%以下較適合,以5%以下更佳,以3.0%以下最理想。薄膜厚度之變動率達10%以上時,光學特性之任一項均增大,不得獲得以色相分歧為目的之光學特性。Further, in the uniaxially stretched laminated film of the present invention, the resin constituting the first layer and the second layer is preferably a crystalline resin as described above. When the resin constituting the first layer and the second layer is a crystalline resin at the same time, the treatment such as stretching does not cause unevenness, and as a result, the thick spot of the film can be reduced. The thickness variation range is preferably 10% or less as shown by the following formula (3), more preferably 5% or less, and most preferably 3.0% or less. When the variation rate of the film thickness is 10% or more, any of the optical characteristics is increased, and optical characteristics for the purpose of discoloration of the hue are not obtained.

厚度變動率(%)=(Tm a x -Tm i n )/(TA v e )………(3)上述式中之Tm a x 為最大厚度、Tm i n 為最小厚度、及TA v e 為平均厚度。Thickness variation rate (%) = (T m a x - T m i n ) / (T A v e ) (3) T m a x in the above formula is the maximum thickness, and T m i n is the minimum thickness And T A v e is the average thickness.

本發明之單軸拉伸層合薄膜,為提升薄膜之捲取性,以在第一層或第二層之一方含有對單軸拉伸層合薄膜之重量為0.001~0.5重量%較適合,以0.005~0.2重量%更佳之惰性微粒為宜。惰性微粒之平均粒徑以0.01~2μm較適合,以0.05~1μm更佳,以0.1~0.3μm最理想。平均粒徑小於下限,含量亦少時下限時,容易使單軸拉伸層合薄膜之提升捲取性的效果不足;另一方面,惰性微粒之含量超過上限,平均粒徑亦超過上限時,由於微粒使多層拉伸薄膜之光學特性顯著惡化,極不適合。The uniaxially stretched laminated film of the present invention is suitable for improving the take-up property of the film, and is preferably 0.001 to 0.5% by weight based on the weight of the uniaxially stretched laminated film on one of the first layer or the second layer. More preferably 0.005 to 0.2% by weight of inert particles are preferred. The average particle diameter of the inert fine particles is preferably 0.01 to 2 μm, more preferably 0.05 to 1 μm, and most preferably 0.1 to 0.3 μm. When the average particle diameter is less than the lower limit and the content is also small, the lower limit is easy, and the effect of improving the take-up property of the uniaxially stretched laminated film is insufficient. On the other hand, when the content of the inert fine particles exceeds the upper limit and the average particle diameter exceeds the upper limit, The microparticles cause a significant deterioration in the optical properties of the multilayer stretched film, which is extremely unsuitable.

<單軸拉伸層合薄膜之製造方法><Method for Producing Uniaxially Stretched Laminate Film>

就最適合之例詳述如下。The most suitable examples are detailed below.

本發明之單軸拉伸層合薄膜,係將熔點為260~270℃之第一熱塑性樹脂,例如以2,6-萘二羧酸乙二醇酯成份為主要重覆單位之聚酯(第一層用),與拉伸處理後之熔點至少比該第一熱塑性樹脂低10℃以上的第二熱塑性樹脂,例如以2,6-萘二羧酸乙二醇酯成份為主要重覆單位之聚酯(第二層用),於熔融狀態交替至少501層以上以重疊狀態擠壓形成多層未拉伸薄膜(形成薄片狀物之步驟)。此時層合501層以上之層合物,其層厚為階段式或連續式於1.5倍~5.0倍之範圍改變而層合。還有,第一熱塑性樹脂及第二熱塑性樹脂之聚酯係與上述的第一層及第二層之說明相同。第一熱塑性樹脂之聚酯的熔點低於260℃時,不能獲得充分之與第二熱塑性樹脂的聚酯之熔點差,結果難以賦予所得單軸拉伸層合薄膜之層間充分的折射率差。另一方面,均聚2,6-萘二羧酸乙二醇酯的熔點為267℃左右之故,第一層用之第一聚酯的熔點上限最高為270℃。又,第二層用之第二聚酯的熔點,不比第一聚酯低15℃以上時不能獲得充分之與第二聚酯的熔點差,結果不能賦予所得單軸拉伸層合薄膜之層間充分的折射率差。第一聚酯之熔點與第二聚酯之熔點差的上限,從維持兩者之密著性的觀點而言,以最高50℃較適合。The uniaxially stretched laminated film of the present invention is a first thermoplastic resin having a melting point of 260 to 270 ° C, for example, a polyester having a main repeating unit of ethylene 2,6-naphthalenedicarboxylate (No. a second thermoplastic resin having a melting point at least 10 ° C lower than the first thermoplastic resin after the stretching treatment, for example, a 2,6-naphthalenedicarboxylate component as a main repeating unit The polyester (for the second layer) is alternately extruded in a molten state by at least 501 layers or more to form a multilayer unstretched film in a superposed state (step of forming a sheet). At this time, a laminate of 501 or more layers is laminated, and the layer thickness thereof is changed in a stepwise or continuous manner in the range of 1.5 times to 5.0 times to be laminated. Further, the polyesters of the first thermoplastic resin and the second thermoplastic resin are the same as those described for the first layer and the second layer described above. When the melting point of the polyester of the first thermoplastic resin is less than 260 ° C, a sufficient difference in melting point from the polyester of the second thermoplastic resin cannot be obtained, and as a result, it is difficult to provide a sufficient refractive index difference between the layers of the obtained uniaxially stretched laminated film. On the other hand, since the melting point of the homopoly 2,6-naphthalenedicarboxylate is about 267 ° C, the upper limit of the melting point of the first polyester for the first layer is at most 270 ° C. Further, the melting point of the second polyester for the second layer is not more than 15 ° C lower than the first polyester, and a sufficient difference in melting point from the second polyester is not obtained, and as a result, the interlayer of the obtained uniaxially stretched laminated film cannot be imparted. A sufficient refractive index difference. The upper limit of the difference between the melting point of the first polyester and the melting point of the second polyester is preferably from 50 to C from the viewpoint of maintaining the adhesion between the two.

如此而得之未拉伸層合薄膜於製膜方向,或與其直交的寬度方向的任一種之單軸方向(沿薄膜面之方向)拉伸。拉伸溫度以第一熱塑性樹脂,例如聚酯之玻璃轉移點溫度(Tg)~(Tg+50℃)之範圍較適合。此時之面積倍率以2~10倍較適合。拉伸倍率愈大,第一層及第二層中之各層的面方向之偏差,藉由拉伸薄層化而減小,即單軸拉伸層合薄膜的光干擾於面方向為均勻之故,甚為適合。此時之拉伸方法可採用藉由棒狀加熱器之加熱拉伸、滾筒加熱拉伸、拉幅器拉伸等眾所周知的拉伸方法,從藉由與滾筒接觸缺陷之減少及拉伸速度等的觀點而言,以拉幅器拉伸較適合。The thus obtained unstretched laminated film is stretched in the uniaxial direction (in the direction of the film surface) in either the film forming direction or the width direction orthogonal thereto. The stretching temperature is preferably in the range of the glass transition point temperature (Tg) to (Tg + 50 ° C) of the first thermoplastic resin such as polyester. At this time, the area magnification is preferably 2 to 10 times. The larger the stretching ratio, the deviation of the surface direction of each of the first layer and the second layer is reduced by stretching thin layering, that is, the light of the uniaxially stretched laminated film is disturbed to be uniform in the plane direction. Therefore, it is very suitable. The stretching method at this time may employ a well-known stretching method such as heating stretching by a rod heater, drum heating stretching, tenter stretching, etc., from the reduction of defects by contact with the roller, the stretching speed, and the like. From the point of view, it is more suitable to stretch with a tenter.

此最適合之方法的最大特徵為,將如此拉伸之層合薄膜於第二熱塑性樹脂例如比聚酯之熔點低10℃的溫度,與第一熱塑性樹脂例如比聚酯之熔點低15℃的溫度之間進行熱處理,緩和第二層內之分子鏈的定向,使第二層之折射率降低。熱處理之溫度,低於第二熱塑性樹脂之熔點超過10℃時,緩和第二層內之分子鏈的定向使折射率降低之效果不足,不能賦予所得單軸拉伸層合薄膜充分之折射率差。另一方面,熱處理之溫度,未低於第一熱塑性樹脂之熔點10℃以上的溫度時,亦緩和第一層內之分子鏈的定向使折射率下降,不能獲得賦予所得單軸拉伸層合薄膜充分之折射率差。適合之處理溫度為低於第二熱塑性樹脂的熔點6℃之溫度,與低於第一熱塑性樹脂之熔點16℃的溫度之間的溫度;以低於第二熱塑性樹脂之熔點2℃的溫度,與低於第一熱塑性樹脂之熔點18℃的溫度之間的溫度更為適合。還有,熱處理之時間以1~60秒較適合。The most characteristic feature of this most suitable method is that the thus stretched laminate film is at a temperature at which the second thermoplastic resin is, for example, 10 ° C lower than the melting point of the polyester, and the first thermoplastic resin is, for example, 15 ° C lower than the melting point of the polyester. The heat treatment between the temperatures moderates the orientation of the molecular chains in the second layer to lower the refractive index of the second layer. When the temperature of the heat treatment is lower than the melting point of the second thermoplastic resin by more than 10 ° C, the effect of lowering the orientation of the molecular chain in the second layer to reduce the refractive index is insufficient, and the sufficient refractive index difference of the obtained uniaxially stretched laminated film cannot be imparted. . On the other hand, when the temperature of the heat treatment is not lower than the melting point of the first thermoplastic resin by 10 ° C or more, the orientation of the molecular chain in the first layer is also relaxed to lower the refractive index, and the obtained uniaxially stretched laminate cannot be obtained. The film has a sufficient refractive index difference. Suitable treatment temperature is a temperature lower than 6 ° C lower than the melting point of the second thermoplastic resin, and a temperature lower than 16 ° C lower than the melting point of the first thermoplastic resin; at a temperature lower than 2 ° C of the melting point of the second thermoplastic resin, A temperature between the temperature lower than the temperature of 18 ° C lower than the melting point of the first thermoplastic resin is more suitable. Also, the heat treatment time is preferably 1 to 60 seconds.

又,藉由改變此熱處理之溫度及時間,不改變樹脂之組成能調整第二層的折射率;即樹脂之組成不改變能改變單軸拉伸層合薄膜的反射特性。Further, by changing the temperature and time of the heat treatment, the refractive index of the second layer can be adjusted without changing the composition of the resin; that is, the composition of the resin is not changed to change the reflection characteristics of the uniaxially stretched laminated film.

<低反射率層><low reflectivity layer>

本發明之單軸拉伸多層層合薄膜,對在上述單軸拉伸層合薄膜之至少一方的面上射入之光,具有表面反射率為3%以下之低反射率層。低反射率層(以下亦為防反射層合層)之表面反射率大於3%時,單軸拉伸層合薄膜之穿透軸側的表面反射之防止效果不足,不能獲得充分之提升亮度的效果。以2%以下為佳,以1%以下更適合。The uniaxially stretched multilayer laminated film of the present invention has a low reflectance layer having a surface reflectance of 3% or less on light incident on at least one surface of the uniaxially stretched laminated film. When the surface reflectance of the low reflectance layer (hereinafter also the antireflection laminate layer) is more than 3%, the surface reflection resistance of the uniaxially stretched laminated film is insufficient to prevent the surface from being sufficiently enhanced. effect. It is preferably 2% or less, and more preferably 1% or less.

本發明中使用之防反射層,不損及單軸拉伸層合薄膜之上述的光學特性時,沒有特別的限制。具體的防反射層有,(1)由厚度0.1μm左右之MgF2 等極薄膜所成的防反射層,(2)藉由形成金屬蒸鍍膜之防反射層,(3)將由光之折射率低的材料所成之低折射率層設置於單軸拉伸層合薄膜之上的防反射層,(4)將折射率高之高折射率層設置單軸拉伸層合薄膜之上,於該折射率層之上設置比該高折射率層之折射率低的低折射率層之防反射層(例如在防反射層中連接於單軸拉伸層合薄膜之部位使具有高折射率的金屬氧化物之超微粒層散佈存在者),(5)重覆上述(4)之層構成而層合的防反射層,(6)在折射率高之高折射率層的內側(膠黏於顯示面之際的顯示面側)設置折射率比該高折射率層之折射率低的中折射率層,在該折射率高之高折射率層的外側(膠黏於顯示面之際的與顯示面相異之側)設置折射率比中折射率層之折射率低的低折射率層之防反射層。The antireflection layer used in the present invention is not particularly limited as long as it does not impair the above optical characteristics of the uniaxially stretched laminate film. The specific antireflection layer includes (1) an antireflection layer made of a film of MgF 2 or the like having a thickness of about 0.1 μm, (2) an antireflection layer formed by forming a metal deposition film, and (3) a refractive index of light. a low refractive index layer formed of a low material is disposed on the uniaxially stretched laminated film, and (4) a high refractive index layer having a high refractive index is disposed on the uniaxially stretched laminated film. An antireflection layer having a lower refractive index layer than the refractive index of the high refractive index layer is disposed on the refractive index layer (for example, a portion of the antireflection layer connected to the uniaxially stretched laminated film to have a high refractive index (6) The ultrafine particle layer of the metal oxide is dispersed, (5) the antireflection layer laminated with the layer of the above (4), and (6) the inner side of the high refractive index layer having a high refractive index (adhesive) a display surface side of the display surface) is provided with a medium refractive index layer having a refractive index lower than that of the high refractive index layer, and is outside the high refractive index layer having a high refractive index (adhesion to the display surface) The side on which the display surface is different) is provided with an antireflection layer of a low refractive index layer having a refractive index lower than that of the medium refractive index layer.

其中從能進行更具效果之防反射的觀點而言,以(4)之低折射率層及(6)之防反射層更為適合。尤其在單軸拉伸層合薄膜上以中折射率層、高折射率層、低折射率層之順序形成者更佳。進而低折射率層、中折射率層及高折射率層為由SiOx 所成,低折射率層之折射率大於1.4、高折射率層之折射率低於2.2,具有低折射率層為80~110nm之厚度、高折射率層為30~110nm之厚度及中折射率層為50~100nm之厚度,且各別之層的光學膜厚D(D=n.d,n:中折射率層之折射率,d:中折射率層之厚度)為可見光之波長以下的防反射層,較為適合。Among them, the low refractive index layer of (4) and the antireflection layer of (6) are more suitable from the viewpoint of enabling more effective antireflection. In particular, it is more preferable to form the medium refractive index layer, the high refractive index layer, and the low refractive index layer in the order of the uniaxially stretched laminated film. Further, the low refractive index layer, the medium refractive index layer, and the high refractive index layer are made of SiO x , the refractive index of the low refractive index layer is greater than 1.4, the refractive index of the high refractive index layer is less than 2.2, and the low refractive index layer is 80. The thickness of ~110nm, the thickness of the high refractive index layer is 30~110nm, the thickness of the medium refractive index layer is 50~100nm, and the optical film thickness D of each layer (D=n.d, n: medium refractive index layer) The refractive index, d: the thickness of the medium refractive index layer) is preferably an antireflection layer having a wavelength of visible light or less.

又,上述低折射率層以具有1.1~1.45之折射率較適合,以1.1~1.4之折射率更佳。折射率低於1.1時,難以獲得防反射之效果,折射率超過1.45時防反射之效果減弱。Further, the low refractive index layer is preferably a refractive index of 1.1 to 1.45, and more preferably a refractive index of 1.1 to 1.4. When the refractive index is less than 1.1, it is difficult to obtain an antireflection effect, and when the refractive index exceeds 1.45, the effect of antireflection is weakened.

低折射率層可藉由將由下述特定之組成所成的塗液首先塗佈於單軸拉伸層合薄膜之至少單面上而得。The low refractive index layer can be obtained by first applying a coating liquid composed of the following specific composition to at least one side of the uniaxially stretched laminated film.

此塗液係由(a)由至少一種選自Si、Al、Ti及Zr所成群之元素的氧化物實質所成之無機微粒及由將其表面被覆之有機聚合物而成的被覆微粒,(b)黏合劑樹脂,及(c)沸點為100℃以上之有機溶劑所成。The coating liquid is composed of (a) inorganic fine particles substantially composed of oxides of at least one element selected from the group consisting of Si, Al, Ti, and Zr, and coated fine particles obtained by coating the surface of the organic polymer. (b) a binder resin, and (c) an organic solvent having a boiling point of 100 ° C or higher.

上述無機微粒以由Si之氧化物實質所成者較適合。The above inorganic fine particles are preferably made of an oxide of Si.

此等無機微粒以烷氧基金屬之部份水解物或經水解物之縮合形成者為佳。此時所謂烷氧基金屬係指上述元素結合烷氧基(-OR基)的物質之意。此時R為低級烷基,例如以甲基、乙基、正丙基、異丙基、正丁基、異丁基較適合。如此之無機微粒以一部份含有羥基、烷氧基較為適合。烷氧基能使無機微粒與後述之將無機微粒改性的目的之有機聚合物或黏合劑樹脂的親和提升,於兩者之間形成化學鍵。又,在有機溶劑中有提升該無機微粒之分散性的作用。烷氧基金屬具有因應其中心元素之價數的烷氧基,本發明中以含有烷氧基3~4個烷氧基金屬較為適合。These inorganic fine particles are preferably formed by partial hydrolysis of a metal alkoxide or condensation by a hydrolyzate. The alkoxy group at this time means a substance in which the above element is bonded to an alkoxy group (-OR group). In this case, R is a lower alkyl group, and for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group is suitable. Such inorganic fine particles are preferably contained in a part containing a hydroxyl group or an alkoxy group. The alkoxy group can enhance the affinity of the inorganic fine particles with the organic polymer or the binder resin for the purpose of modifying the inorganic fine particles described later, and form a chemical bond therebetween. Further, in the organic solvent, there is an effect of improving the dispersibility of the inorganic fine particles. The metal alkoxide has an alkoxy group in accordance with the valence of its central element, and in the present invention, a metal having 3 to 4 alkoxy groups containing an alkoxy group is suitable.

上述無機微粒之粒徑以5~200nm的範圍較為適合。The particle diameter of the inorganic fine particles is preferably in the range of 5 to 200 nm.

將無機微粒之表面被覆的有機聚合物有例如烷基系聚合物,具有胺基甲酸酯鍵之聚合物,具有酯鍵之聚合物,具有醚鍵之聚合物,丙烯酸系聚合物等。其中從折射率之調整容易,透明性優越的觀點而言,以丙烯酸系聚合物較為適合。又,有機聚合物具有至少一個之聚矽氧烷基,且該聚矽氧烷基中含有一個以上之烷氧基,從分散性等的觀點而言極為適合。烷氧基之例為與上述相同之基。又,如此之有機聚合物以含有氟元素為佳。The organic polymer coated with the surface of the inorganic fine particles is, for example, an alkyl polymer, a polymer having a urethane bond, a polymer having an ester bond, a polymer having an ether bond, an acrylic polymer or the like. Among them, an acrylic polymer is suitable from the viewpoint of easy adjustment of the refractive index and superior transparency. Further, the organic polymer has at least one polyoxyalkylene group, and the polyoxyalkylene group contains one or more alkoxy groups, and is extremely suitable from the viewpoint of dispersibility and the like. Examples of the alkoxy group are the same as those described above. Further, such an organic polymer preferably contains a fluorine element.

本發明中上述被覆微粒之粒徑以5~200nm的範圍較適合。低於5μm時微粒的表面能量增高之故容易在塗液中凝聚,超過200nm時所得塗膜之透明性不足。In the present invention, the particle diameter of the coated fine particles is preferably in the range of 5 to 200 nm. When the surface energy of the fine particles is less than 5 μm, it is likely to aggregate in the coating liquid, and when it exceeds 200 nm, the transparency of the obtained coating film is insufficient.

黏合劑樹脂(b)沒有特別的限制,有烷基系聚合物,具有胺基甲酸酯鍵之聚合物,具有酯鍵之聚合物,聚有醚鍵之聚合物,丙烯酸系聚合物等。其中,從透明性優越之點而言以丙烯酸系聚合物更為適合。丙烯酸系聚合物沒有特別的限制,有例如由(甲基)丙烯酸甲酯、(甲基)丙烯酸乙酯、(甲基)丙烯酸丙酯、(甲基)丙烯酸異丙酯、(甲基)丙烯酸異丁酯、(甲基)丙烯酸叔丁酯、(甲基)丙烯酸3-羥基乙基酯等單官能丙烯酸酯、二(甲基)丙烯酸乙二醇酯、二(甲基)丙烯酸丙二醇酯、(甲基)丙烯酸丁二醇酯等二官能丙烯酯等具有丙烯基之單體聚合的聚合物等等。又,至少一方之末端具有丙烯基之烷基聚合、醚聚合物等,進而此等聚合物之支鏈具有反應性的官能基:例如羥基、羧基、胺基、環氧基、巰基、噁唑啉基等之聚合物亦適合使用。本發明中具有如此等之丙烯基的聚合物亦稱為丙烯基系聚合物。此等之中,從與後述之硬化劑的反應考慮時,以結構之一部份中含有羥基的丙烯酸系聚合物較為適合。The binder resin (b) is not particularly limited, and is an alkyl polymer, a polymer having a urethane bond, a polymer having an ester bond, a polymer having an ether bond, an acrylic polymer, and the like. Among them, an acrylic polymer is more suitable from the viewpoint of superior transparency. The acrylic polymer is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, and (meth)acrylic acid. a monofunctional acrylate such as isobutyl ester, tert-butyl (meth)acrylate or 3-hydroxyethyl (meth)acrylate; ethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; A polymer having a propylene group polymerized such as a difunctional acrylate such as (meth) acrylate or the like. Further, at least one of the terminals has an alkyl group polymerization of an acryl group, an ether polymer or the like, and further a functional group having a reactive chain such as a hydroxyl group, a carboxyl group, an amine group, an epoxy group, a decyl group or an oxazole. Polymers such as phenyl groups are also suitable for use. The polymer having such a propylene group in the present invention is also referred to as a propylene-based polymer. Among these, an acrylic polymer containing a hydroxyl group in one part of the structure is suitable from the viewpoint of the reaction with a curing agent to be described later.

沸點為100℃以上之可與水混合的有機溶劑(c)有丙二醇單甲醚(PGM、沸點121℃)、丙二醇單甲醚乙酸酯(PGMA、沸點146℃)、乙二醇單丁醚(EGB、沸點171℃)、甲異丁酮(MIBK、沸點115℃)、乙酸異丁酯(IBAc、沸點127℃)、甲正丁酮(MNBK、沸點128℃)等等。其中以甲異丁酮、乙酸異丁酯、甲正丁酮較為適合,以甲異丁酮最適合。在如甲苯、甲乙酮等沸點低於100℃不能與水混合之溶劑中,即使改變固形份濃度,所得低折射率層之折射率亦幾乎完全沒改變。使用沸點為100℃以上,以100~150℃更佳,以100~130℃最適合之有機溶劑時,構成低折射率之固形份的組成即使相同,藉由改變固形份濃度等塗液之組成有能調整所得低折射率層之折射率的優點。溶劑之沸點低於下限時,不能實現本發明之低折射率;高於上限時,生產之際使線上速度遲緩,必要將烘箱之溫度提高設定,甚不適合。又,上述有機溶劑必要能與水混合,於此所謂能與水混合係指具有羥基、羰基等極性基之意,例如對該有機溶劑將1重量%以上,以5重量%更適合之水均勻混合的狀態之意。具有不必改變構成低折射率之固形份的組成,即可調整折射率之優點,能對應單一組成之各式各樣的折射率。即,低折射率不僅折射率低,為能因應形成之基材薄膜的折射率,滿足各別振幅條件的最適折射率之故,對複數之基材薄膜,即使不準備形成複數之低折射率層的材料,以單一之組成可獲得接近最適的折射率之層的優點極大。有機溶劑之沸點低於100℃時,在塗佈後的乾燥之際溶劑急激揮發,不能獲得均勻的空隙之故,看不到折射率的改變。又,在塗佈後的乾燥之際,藉由以氣化熱使塗液溫度下降將空氣中之水份一度捲入塗液中後揮發時,形成溶劑與水之揮發速度的梯度以致乾燥不均勻,塗膜內形成大的空隙使塗膜之透明度降低,必要使用能與水混合,且混合後之溶劑的揮發速度差小的高沸點溶劑。The organic solvent (c) having a boiling point of 100 ° C or more and mixed with water is propylene glycol monomethyl ether (PGM, boiling point 121 ° C), propylene glycol monomethyl ether acetate (PGMA, boiling point 146 ° C), ethylene glycol monobutyl ether (EGB, boiling point 171 ° C), methyl isobutyl ketone (MIBK, boiling point 115 ° C), isobutyl acetate (IBAc, boiling point 127 ° C), methyl n-butanone (MNBK, boiling point 128 ° C) and the like. Among them, methyl isobutyl ketone, isobutyl acetate, and methyl n-butanone are suitable, and methyl isobutyl ketone is most suitable. In a solvent such as toluene or methyl ethyl ketone which does not mix with water at a boiling point of less than 100 ° C, the refractive index of the obtained low refractive index layer hardly changes at all even if the solid content concentration is changed. When the boiling point is 100 ° C or higher, 100 to 150 ° C is more preferable, and the most suitable organic solvent is 100 to 130 ° C, the composition of the solid component constituting the low refractive index is the same, and the composition of the coating liquid is changed by changing the solid content concentration or the like. There is an advantage that the refractive index of the resulting low refractive index layer can be adjusted. When the boiling point of the solvent is lower than the lower limit, the low refractive index of the present invention cannot be achieved; when the upper limit is exceeded, the line speed is slow at the time of production, and it is necessary to increase the temperature of the oven, which is not suitable. Further, the organic solvent may be mixed with water. The term "mixable with water" means having a polar group such as a hydroxyl group or a carbonyl group. For example, the organic solvent is preferably 1% by weight or more, and more preferably 5% by weight. The meaning of the mixed state. It has the advantage of adjusting the refractive index without changing the composition of the solid component constituting the low refractive index, and can correspond to various refractive indices of a single composition. In other words, the low refractive index is not only low in refractive index, but also the refractive index of the base film which can be formed, and the optimum refractive index of each of the amplitude conditions is satisfied. Therefore, even if a plurality of low refractive indexes are not prepared for the plurality of base films. The material of the layer has the advantage of obtaining a layer close to the optimum refractive index in a single composition. When the boiling point of the organic solvent is less than 100 ° C, the solvent is rapidly volatilized during drying after coating, and a uniform void cannot be obtained, so that a change in refractive index is not observed. Moreover, when the coating is dried, the temperature of the coating liquid is lowered by the heat of vaporization, and the water in the air is once entangled in the coating liquid and then volatilized, thereby forming a gradient of the evaporation rate of the solvent and the water so that the drying does not occur. Evenly, a large void is formed in the coating film to lower the transparency of the coating film, and it is necessary to use a high boiling point solvent which can be mixed with water and has a small difference in volatilization rate of the solvent after mixing.

可是,如上所述,低折射率層不僅折射率愈低愈佳因應所使用之薄膜基材的折射率,為滿足各別振幅條件之最適折射率。例如薄膜基材為聚萘二羧酸乙二醇酯薄膜時,可獲得如上述特開2003-292805號公報所提案之折射率,即折射率為1.3以上之低折射率層時亦具良好的防反射性能;如聚對苯二甲酸乙二醇酯薄膜或三乙醯基纖維素之薄膜基材時,折射率為1.3以上之低折射率層時不能獲得良好的防反射性能。不過,依本發明之方法,成功的在薄膜基材之表面形成折射率如1.10~1.29之低折射率的低折射率層。However, as described above, the lower the refractive index of the low refractive index layer, the better the refractive index of the film substrate to be used, and the optimum refractive index satisfying the respective amplitude conditions. For example, when the film substrate is a polyethylene naphthalate film, a refractive index as disclosed in the above-mentioned JP-A-2003-292805, that is, a low refractive index layer having a refractive index of 1.3 or more can be obtained. Antireflection performance; when a film substrate such as polyethylene terephthalate film or triethylenesulfonyl cellulose, a low refractive index layer having a refractive index of 1.3 or more cannot obtain good antireflection performance. However, according to the method of the present invention, a low refractive index layer having a low refractive index of 1.10 to 1.29 is formed on the surface of the film substrate.

獲得如此之特別低的折射率之方法有例如使塗液中之固形份濃度降低,可與水混合且沸點為100℃以上之有機溶劑的比例增加,或選擇塗佈後的乾燥之際容易餘留在塗佈膜內的有機溶劑等。從如此之觀點而言,可與水混合且沸點為100℃以上之有機溶劑,在塗液中之含量為70重量%以上,以80重量%以上更適合,以90重量%以上更佳,以使用95重量%以上最理想。使用量少於此範圍時,於乾燥之際難以在低折射率層形成空隙,經存在於塗液中之其他溶劑的揮發時之對流,在乾燥時低折射率層有霧白之可能。又,塗刷時形成低折射率層之固形份濃度為0.5~10重量%之範圍,進而於0.5~5重量之範圍容易實施折射率的調整之故,極為適合。又,從更降低折射率之觀點而言,固形份成份濃度以0.5~2重量%更適合,以0.5~1.8重量%最理想。於此範圍以外,為使所得低折射率層之厚度達到具有充分的反射特性之必要的厚度,極為困難。The method of obtaining such a particularly low refractive index is, for example, a reduction in the concentration of the solid portion in the coating liquid, an increase in the ratio of the organic solvent which can be mixed with water and having a boiling point of 100 ° C or more, or the selection of the drying after coating is easy. An organic solvent or the like remaining in the coating film. From such a viewpoint, the organic solvent which can be mixed with water and has a boiling point of 100 ° C or more is more preferably 70% by weight or more in the coating liquid, more preferably 80% by weight or more, and even more preferably 90% by weight or more. It is most desirable to use 95% by weight or more. When the amount used is less than this range, it is difficult to form voids in the low refractive index layer during drying, and convection occurs when volatilization of other solvents present in the coating liquid, and the low refractive index layer may be fogged during drying. Further, the solid content concentration of the low refractive index layer formed during the coating is in the range of 0.5 to 10% by weight, and further, the refractive index is easily adjusted in the range of 0.5 to 5 by weight, which is extremely suitable. Further, from the viewpoint of lowering the refractive index, the solid content concentration is more preferably 0.5 to 2% by weight, and most preferably 0.5 to 1.8% by weight. Outside of this range, it is extremely difficult to make the thickness of the obtained low refractive index layer to have a thickness necessary for sufficient reflection characteristics.

薄膜基材之厚度沒有特別的限制,以200μm以下較適合。比200μm厚時剛性過強,所得防反射薄膜膠黏於顯示器時之處理困難。The thickness of the film substrate is not particularly limited, and is preferably 200 μm or less. When the thickness is thicker than 200 μm, the rigidity is too strong, and the obtained antireflection film is difficult to handle when it is adhered to the display.

本發明中所使用之上述塗液,以另含有下述式所示之烷氧基化合物更為適合。The coating liquid used in the present invention is more preferably further contained in an alkoxy compound represented by the following formula.

(R1 O)n MR2 m n 式中,R1 及R2 為互相獨立之碳數1~4的烷基,M為Al、Si、Ti或Zr,m為相等於M的原子價之數,n為2~m之數。(R 1 O) n MR 2 m - n wherein R 1 and R 2 are mutually independent alkyl groups having 1 to 4 carbon atoms, M is Al, Si, Ti or Zr, and m is an atomic valence equal to M The number, n is the number of 2 ~ m.

如此之烷氧基化合物,具有將被覆微粒固定於低折射率層內之功能。Such an alkoxy compound has a function of fixing the coated fine particles in the low refractive index layer.

以上述式表示之化合物中,以可水解之物質較適合,具體的以甲基三乙醯氧基矽烷、二甲基二乙醯氧基矽烷、三甲乙醯氧基矽烷、四乙醯氧基矽烷、四甲氧基矽烷、四乙氧基矽烷、四異丙氧基矽烷、四異丁氧基矽烷、甲基三乙氧基矽烷、二甲基二乙氧基矽烷、三甲基乙氧基矽烷、苯基三乙氧基矽烷等較為適合。又,為有效進行形成上述低折射率層之黏合劑樹脂與將被覆微粒表面被覆之有機聚合物的水解縮合,亦可含有催化劑。催化劑可使用酸性催化劑或鹼性催化劑。酸性催化劑以例如鹽酸、硝酸等無機酸、乙酸、檸檬酸、丙酸、草酸、對-苯磺酸等有機酸較適合。鹼性催化劑以例如氨、三乙胺、三丙胺等有機胺化合物、甲氧基鈉、甲氧基鉀、乙氧基鉀、氫氧化鈉、氫氧化鉀等鹼金屬化合物較適合。Among the compounds represented by the above formula, hydrolyzable substances are preferred, and specific examples are methyltriethoxydecane, dimethyldimethoxydecane, trimethylacetoxydecane, tetraethoxycarbonyl. Decane, tetramethoxy decane, tetraethoxy decane, tetraisopropoxy decane, tetraisobutoxy decane, methyl triethoxy decane, dimethyl diethoxy decane, trimethyl ethoxy Alkane, phenyltriethoxydecane, etc. are suitable. Further, a catalyst may be contained in order to effectively carry out hydrolysis and condensation of the binder resin forming the low refractive index layer and the organic polymer covering the surface of the coated fine particles. The catalyst may use an acidic catalyst or a basic catalyst. The acidic catalyst is preferably an inorganic acid such as hydrochloric acid or nitric acid, an organic acid such as acetic acid, citric acid, propionic acid, oxalic acid or p-benzenesulfonic acid. The basic catalyst is preferably an organic metal compound such as ammonia, triethylamine or tripropylamine, an alkali metal compound such as sodium methoxide, potassium methoxide, potassium ethoxide, sodium hydroxide or potassium hydroxide.

為進行充分之水解必要的塗液之熟化時間,依存於塗液之pH、環境溫濕度,以1小時以上之熟化較為適合。The aging time of the coating liquid necessary for sufficient hydrolysis depends on the pH of the coating liquid, the ambient temperature and humidity, and is preferably aged for more than one hour.

本發明中之塗液,可另含有黏合劑樹脂(b)之交聯劑。此交聯劑於塗膜乾燥時,使黏合劑樹脂交聯而硬化。The coating liquid in the present invention may further contain a crosslinking agent of the binder resin (b). The crosslinking agent crosslinks and hardens the binder resin when the coating film is dried.

如此之交聯劑有多官能異氰酸酯化合物、三聚氰胺化合物、胺基塑料樹脂等,其中從處理容易之點而言以多官能異氰酸酯系化合物更為適合。如此之多官能異氰酸酯系化合物有例如甲苯烯二異氰酸酯、苯二甲基二異氰酸酯、二苯基甲烷二異氰酸酯、六亞甲基二異氰酸酯、1,6-六亞甲基二異氰酸酯之二聚物、三聚異氰酸酯等之三聚物等等。又,尚有此等多官能異氰酸酯類與多價醇反應生成之餘留兩個以上異氰酸酯基的化合物、肟類、內醯胺類等以封閉劑封閉之封端基多官能異氰酸酯化合物等等。Such a crosslinking agent may be a polyfunctional isocyanate compound, a melamine compound, an amine-based plastic resin or the like, and a polyfunctional isocyanate-based compound is more suitable from the viewpoint of ease of handling. Such polyfunctional isocyanate-based compounds are, for example, toluene diisocyanate, benzodimethyl diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate dimer, a terpolymer of a trimeric isocyanate or the like. Further, a blocked polyfunctional isocyanate compound blocked with a blocking agent such as a compound obtained by reacting such a polyfunctional isocyanate with a polyvalent alcohol, which contains two or more isocyanate groups, an anthraquinone or an indoleamine, and the like may be used.

本發明中低折射率膜可藉由塗佈於單軸拉伸層合薄膜之上而設置。塗佈方法可使用隨意之眾周知的方法。有例如唇型直接法、小點塗佈法、狹縫逆塗法、模頭塗佈法、凹版滾筒塗佈法、刮板塗佈法、噴霧塗佈法、氣動刮塗法、浸漬塗佈法、棒桿塗佈法等等。使用熱固性樹脂為黏合劑時,低折射化合物之塗設係將含有形成各別之成份的塗液塗佈於基材,經加熱乾燥形成塗膜。加熱條件為80~160℃下10~120秒,以100~150℃下20~60秒更適合。使用UV硬化性樹脂或EB硬化性樹脂為黏合劑時,一般上在進行預備乾燥後,施行紫外線照射或電子線照射。The low refractive index film of the present invention can be provided by being applied on a uniaxially stretched laminated film. The coating method can be carried out by a method which is well known in the art. For example, lip direct method, small dot coating method, slit reverse coating method, die coating method, gravure coating method, blade coating method, spray coating method, pneumatic blade coating method, dip coating Method, rod coating method, etc. When a thermosetting resin is used as the binder, the coating of the low refractive compound is applied to the substrate by coating liquid containing the respective components, and dried by heating to form a coating film. The heating condition is 10 to 120 seconds at 80 to 160 ° C, and 20 to 60 seconds at 100 to 150 ° C is more suitable. When a UV curable resin or an EB curable resin is used as the binder, ultraviolet irradiation or electron beam irradiation is generally performed after preliminary drying.

[實施例][Examples]

以實施例更詳細說明本發明如下。還有,實施例中之物性及特性係以下述的方法測定或評估。The invention is illustrated in more detail by way of examples. Further, the physical properties and characteristics in the examples were measured or evaluated by the following methods.

(1)聚酯樹脂之熔點及玻璃轉點(Tg)採取聚酯樹脂試料10mg,使用DSC(TA儀器公司製,商品名:DSC 2920),以20℃/分鐘之升溫速度測定熔點。(1) The melting point of the polyester resin and the glass transition point (Tg) were 10 mg of a polyester resin sample, and the melting point was measured at a temperature elevation rate of 20 ° C /min using DSC (trade name: DSC 2920, manufactured by TA Instruments Co., Ltd.).

(2)各層之厚度將試料切成三角形,固定於收納膠囊後之環氧樹脂包埋。然後將收納之試料以切薄片機(烏魯多拉卡多-S,萊里魯多公司製)沿製膜方向與厚度方向剪切成厚度50nm之薄膜切片。使用穿透型電子顯微鏡(日本電子股份有限公司製,商品名:JEM2010)將所得薄膜切片以加速電壓100kV觀察並攝影,由照相測定各層之厚度。表1中所示之層厚的定義如下述所示層厚比:第一層之中0.05~0.5的範圍之層的平均厚度(3)藉由DSC測定薄膜之熔點,結晶化尖峰採取10mg之試料薄膜,使用DSC(TA儀器公司製,商品名:DSC2920),以20℃/分鐘之升溫速度測定結晶化溫度及熔點。(2) Thickness of each layer The sample was cut into a triangle shape and fixed in an epoxy resin embedded in a capsule. Then, the sample to be stored was cut into a film slice having a thickness of 50 nm in a film forming direction and a thickness direction by a sheet cutting machine (Uludo Lacado-S, manufactured by Lelyrudo Co., Ltd.). The obtained film sections were observed and photographed at an acceleration voltage of 100 kV using a transmission electron microscope (manufactured by JEOL Ltd., trade name: JEM2010), and the thickness of each layer was measured by photography. The layer thicknesses shown in Table 1 are defined as the layer thickness ratios shown below: the average thickness of the layer in the range of 0.05 to 0.5 in the first layer (3) The melting point of the film is determined by DSC, and the crystallization peak is taken as 10 mg. The sample film was subjected to DSC (manufactured by TA Instruments, trade name: DSC2920), and the crystallization temperature and melting point were measured at a temperature increase rate of 20 ° C /min.

(4)反射率、反射波長使用分光光度計(島津製作所股份有限公司製,MPC-3100),在光源側安裝偏光過濾片,於波長400~800nm之範圍測定於各波長之與鋁蒸鍍鏡面的相對鏡面反射率。此時,將偏光過濾片之穿透軸與薄膜之拉伸方向吻合配置時之測定值做為P偏光,將偏光過濾片之穿透軸與薄膜之拉伸方向成直交配置時之測定值做為S偏光。就分別之偏光成份於400~800nm的範圍之反射率的平均值為平均反射率,將測定之反射率中的最大為最大反射率,最小者為最小反射率。表3中的最大反射率差以下述之式表示。(4) Reflectance and reflection wavelength A spectrophotometer (MPC-3100, manufactured by Shimadzu Corporation) was used, and a polarizing filter was attached to the light source side, and the wavelength of 400 to 800 nm was measured at each wavelength and the aluminum vapor-deposited mirror surface. Relative specular reflectivity. In this case, the measured value when the transmission axis of the polarizing filter is aligned with the stretching direction of the film is P-polarized, and the measured value when the transmission axis of the polarizing filter is orthogonal to the stretching direction of the film is made. For S polarized light. The average value of the reflectance of the respective polarizing components in the range of 400 to 800 nm is the average reflectance, and the maximum of the measured reflectances is the maximum reflectance, and the smallest is the minimum reflectance. The maximum reflectance difference in Table 3 is expressed by the following formula.

最大反射率(%)=最大反射率(%)-最小反射率(%)(5)低折射率膜之厚度及折射率低折射率膜之膜厚及折射率係藉由反射分光膜厚計(大塚電子公司製,商品名:FE-3000),測定300~800nm之反射率,引用n-k科希之分散公式做為代表折射率的波長分散之近似式,藉由與光譜之實測值固定求出膜厚與折射率。Maximum reflectance (%) = maximum reflectance (%) - minimum reflectance (%) (5) thickness of low refractive index film and refractive index film thickness and refractive index of low refractive index film by reflection spectroscopic film thickness meter (Manufactured by Otsuka Electronics Co., Ltd., trade name: FE-3000), the reflectance of 300-800 nm is measured, and the dispersion formula of n-k Koch is used as an approximation of the wavelength dispersion representing the refractive index, by the measured value of the spectrum The film thickness and the refractive index were fixed.

(5)斷裂強度製膜方向之斷裂強度係將試料薄膜切成試料寬(寬度方向010mm、長度(製膜方向)150mm、以夾盤間100mm、拉伸速度100mm/分鐘、圖表速度500m/分鐘之條件,使用因斯多龍型之萬能拉伸試驗裝置將試料拉伸。然後由所得載重-延伸曲線測定斷裂強度。(5) Breaking strength The breaking strength in the film forming direction was obtained by cutting the sample film into a sample width (width direction 010 mm, length (film forming direction) 150 mm, 100 mm between chucks, stretching speed 100 mm/min, chart speed 500 m/min). Under the conditions, the sample was stretched using an Instron type universal tensile test apparatus, and then the breaking strength was measured from the obtained load-extension curve.

又,寬度方向之斷裂強度,除將試料薄膜切成試料寬(製膜方向)10mm、長度(寬度方向)150mm以外,與測定製膜方向之斷裂強度同樣的進行。In addition, the breaking strength in the width direction was measured in the same manner as in the measurement of the breaking strength in the film forming direction except that the sample film was cut into a sample width (film forming direction) of 10 mm and a length (width direction) of 150 mm.

(7)熱收縮率於150℃處理30分鐘時之熱收縮率,係在溫度設定於150℃之烘箱中無拉伸狀態下將薄膜保持30分鐘,以加熱處理前後之尺寸改變做為熱收縮率,藉由下述式算出。(7) The heat shrinkage rate of the heat shrinkage rate at 150 ° C for 30 minutes was maintained in an oven at a temperature set at 150 ° C for 30 minutes without stretching, and the dimensional change before and after the heat treatment was taken as heat shrinkage. The rate is calculated by the following formula.

熱收縮率%=[(L0-L)/L0]×100 L0:熱處理前之標記間距離L:熱處理後之標記間距離又,於200℃處理10分鐘時之熱收縮率,係在溫度設定於200℃之烘箱中無拉伸狀態下將薄膜保持10分鐘,以加熱處理前後之尺寸改變做為熱收縮率,藉由上述式算出。Heat shrinkage rate %=[(L0-L)/L0]×100 L0: distance between marks L before heat treatment: distance between marks after heat treatment, and heat shrinkage rate at 10 °C for 10 minutes, at temperature setting The film was held in an oven at 200 ° C for 10 minutes without stretching, and the dimensional change before and after the heat treatment was taken as the heat shrinkage rate, and was calculated by the above formula.

(8)厚度變動率將切成製膜方向及寬度方向分別為1m×1m之薄膜試料,再剪切成沿縱方向及橫方向分別為2cm寬之25片,使用電子測微計及記錄器(安立電氣股份有限公司製K-312A、K-310B)連續測定各試料之厚度。由全測定值算出平均厚度,進而將測定值細分為每200mm,讀取其中之最大值與最小值,藉由下式算出對平均厚度之厚度變動率。(8) The thickness variation rate is cut into film samples having a film forming direction and a width direction of 1 m × 1 m, respectively, and then sheared into 25 pieces each having a width of 2 cm in the longitudinal direction and the lateral direction, using an electronic micrometer and a recorder. (K-312A, K-310B, manufactured by Anritsu Electric Co., Ltd.) The thickness of each sample was continuously measured. The average thickness was calculated from the total measured value, and the measured value was further subdivided into 200 mm, and the maximum value and the minimum value were read, and the thickness variation rate with respect to the average thickness was calculated by the following formula.

厚度之變動率(%)=(Tm a x -Tm i n )/Ta v e 於此,上述式中之Tm a x 為厚度之最大值,Tm i n 為厚度之最小值,及Ta v e 為平均厚度。The rate of change of thickness (%) = (T m a x - T m i n ) / T a v e where, T m a x in the above formula is the maximum value of thickness, and T m i n is the minimum thickness And T a v e is the average thickness.

(9)層間之密著性將24mm寬之黏著膠帶(尼吉邦公司製,商品名:榭洛鐵布)100mm膠粘於試料薄膜(10mm×50mm),以180度之剝離角剝離後,觀察剝離面。將各10個試料進行試驗,算出產生層間剝離之次數。(9) Adhesive between layers The adhesive tape of 24 mm width (manufactured by Nichib Co., Ltd., trade name: 榭洛铁布) was adhered to a sample film (10 mm × 50 mm), and peeled off at a peel angle of 180 degrees. Stripping the surface. Each of the 10 samples was tested to calculate the number of times the interlayer peeling occurred.

(10)色相之分歧對標準光源C,由試料薄膜之穿透光譜,以JISZ8729為基準在L a b 表色系中求出L 、a 、及b 。藉由下述式求出ab色品(c ab),並評估與無彩色之彩度的分歧。(10) Differences in Hue For the standard light source C, L * , a * , and b * are obtained from the L * a * b * color system based on the JISZ8729 penetration spectrum of the sample film. The ab chromaticity product (c * ab) was obtained by the following formula, and the difference from the chroma of achromatic color was evaluated.

C ab={(a )2 +(b )2 }1 / 2 ○:C ab低於5,極為優異△:C ab為5以上10以下,可實用×:C ab為10以上,不能實用(11)提升亮度效果將試料薄膜插入LCD面板(奇美公司製CMV CT-529A)中之偏光板與擴散薄膜之間,以多普空公司製之亮度計(BM7)測定分離500mm處之以PC表示白色時的正面亮度,算出對試料薄膜插入前之試料薄膜插入後的亮度上升率,評估亮度之提升效果。C * ab = {(a * ) 2 + (b * ) 2 } 1 / 2 ○: C * ab is less than 5 and is extremely excellent Δ: C * ab is 5 or more and 10 or less, and is practical ×: C * ab is 10 or more, it is not practical. (11) Enhancing the brightness effect The sample film is inserted between the polarizing plate and the diffusion film in the LCD panel (CMV CT-529A, manufactured by Chi Mei Co., Ltd.), and separated by a brightness meter (BM7) manufactured by Doppler. The front side brightness at the time of white was expressed by PC at 500 mm, and the brightness increase rate after the sample film insertion before the sample film insertion was calculated, and the effect of improving the brightness was evaluated.

◎:亮度上升率為150%以上○:亮度上升率為140%以上150%以下×:亮度上升率低於140%(12)表面反射率使用島津製作所股份有限公司製之UV-3101PC型,於光源側設置吸收型偏光過濾片,在不形成防反射薄膜之防反射層側塗佈黑色塗料,在形成防反射層側照射光線,測定P偏光及S偏光分別於300~800nm之範圍的反射率,將可見度高之500~600nm的反射率之平均值做為表面反射率◎: The brightness increase rate is 150% or more ○: The brightness increase rate is 140% or more and 150% or less ×: The brightness increase rate is less than 140% (12) The surface reflectance is UV-3101PC type manufactured by Shimadzu Corporation. An absorbing type polarizing filter is disposed on the light source side, and a black paint is applied to the antireflection layer side where the antireflection film is not formed, and light is irradiated on the side where the antireflection layer is formed, and the reflectance of the P polarized light and the S polarized light in the range of 300 to 800 nm is measured. The average value of the reflectance of 500 to 600 nm with high visibility is used as the surface reflectance.

[實施例1][Example 1]

在特性黏度(鄰-氯苯酚,35℃)0.62之聚2,6-萘二羧酸乙二醇酯(PEN)中,加入真球狀二氧化矽微粒(平徑粒徑:0.3μm,長徑與短徑之比:1.02,粒徑之平均偏差:0.1)0.15重量%做為第一層用聚酯;準備特性黏度(鄰-氯苯酚,35℃)0.62之對苯二甲酸10莫耳%共聚合之聚2,6-萘二羧酸乙二醇酯(TA10PEN)做為第二層用聚酯。然後將第一層用聚酯及第二層用聚酯分別於170℃乾燥5小時後,供應於擠壓機,加熱至300℃使為熔融狀態,將第一層用聚酯分歧為301層,第二層用聚酯分歧為300層後,第一層與第二層交替層合,且層厚採用以最大/最小3倍為止連續改變之多層進料單元裝置,保持其層合狀態直接導入模頭,於鑄造鼓上將第一層與第二層之各層的厚度調整為1.0:2.0進行鑄造,即製成第一層與第二層交替層合總數601層之未拉伸層合薄膜。將此未拉伸層合薄膜於135℃之溫度進行寬度方向5.2倍拉伸,於245℃施行3秒鐘之熱固定處理。所得單軸拉伸層合薄膜之厚度為55μm。In the polyethylene (2,6-naphthalenedicarboxylate) (PEN) having an intrinsic viscosity (o-chlorophenol, 35 ° C) of 0.62, true spherical cerium oxide particles (diameter: 0.3 μm, long) Ratio of diameter to short diameter: 1.02, average deviation of particle size: 0.1) 0.15 wt% as polyester for first layer; preparation of intrinsic viscosity (o-chlorophenol, 35 ° C) 0.62 of terephthalic acid 10 mol The % copolymerized polyethylene 2,6-naphthalene dicarboxylate (TA10PEN) is used as the second layer polyester. Then, the first layer polyester and the second layer polyester were respectively dried at 170 ° C for 5 hours, and then supplied to an extruder, heated to 300 ° C to be in a molten state, and the first layer was divided into 301 layers by polyester. After the second layer is divided into 300 layers by polyester, the first layer and the second layer are alternately laminated, and the layer thickness is controlled by a multi-layer feeding unit continuously changing at a maximum/minimum of 3 times to maintain the lamination state directly. Introducing a die, and casting the thickness of each layer of the first layer and the second layer on the casting drum to 1.0:2.0 for casting, that is, making the first layer and the second layer alternately laminating a total of 601 layers of unstretched lamination film. The unstretched laminated film was stretched 5.2 times in the width direction at a temperature of 135 ° C, and heat-fixed at 245 ° C for 3 seconds. The thickness of the obtained uniaxially stretched laminated film was 55 μm.

將含有以氟化有機化合物潤飾之中空二氧化矽微粒,以矽烷偶合劑與丙烯酸樹脂為主成份之市售的低折射率形成用塗佈材料(日本催化劑股份有限公司製,商品名PX2-LR7)5g,與MIBK66.2g,異氰酸酯系硬化劑0.12g混合攪拌10分鐘,即調製成塗佈液。將此塗佈液以邁耶棒塗佈於單軸拉伸層合薄膜之單面上,於150℃之溫度下乾燥。進行硬化反應1分鐘,即得低折射率層。以邁耶棒之順序將塗膜厚度調整於110nm。所得單軸拉伸多層層合薄膜之物性如表3及表4所示。A commercially available low-refractive-index forming coating material containing hollow cerium oxide fine particles retouched with a fluorinated organic compound, and a decane coupling agent and an acrylic resin as a main component (manufactured by Nippon Co., Ltd., trade name PX2-LR7) 5 g of the mixture was mixed with MIBK 66.2 g and 0.12 g of an isocyanate-based curing agent for 10 minutes to prepare a coating liquid. This coating liquid was applied on a single surface of a uniaxially stretched laminated film with a Meyer rod, and dried at a temperature of 150 °C. The hardening reaction was carried out for 1 minute to obtain a low refractive index layer. The film thickness was adjusted to 110 nm in the order of Meyer rods. The physical properties of the obtained uniaxially stretched multilayer laminated film are shown in Tables 3 and 4.

此單軸拉伸多層層合薄膜之低折射率層的反射率為1.24。The reflectance of the low refractive index layer of this uniaxially stretched multilayer laminated film was 1.24.

[實施例2][Embodiment 2]

除賦予雙面塗佈以外,與實施例1同樣的進行,即得單軸拉伸多層層合薄膜。所得單軸拉伸多層層合薄膜之物性如表3及表4所示。此單軸拉伸多層層合薄膜之低折射率層的反射率為1.24。The uniaxially stretched multilayer laminated film was obtained in the same manner as in Example 1 except that the double-sided coating was applied. The physical properties of the obtained uniaxially stretched multilayer laminated film are shown in Tables 3 and 4. The reflectance of the low refractive index layer of this uniaxially stretched multilayer laminated film was 1.24.

[比較例1][Comparative Example 1]

除不賦予雙面塗佈以外,與實施例1同樣的進行,即得單軸拉伸多層層合薄膜。所得單軸拉伸多層層合薄膜之物性如表3及表4所示。The uniaxially stretched multilayer laminated film was obtained in the same manner as in Example 1 except that the double-sided coating was not applied. The physical properties of the obtained uniaxially stretched multilayer laminated film are shown in Tables 3 and 4.

[實施例3][Example 3]

在比較例1所得之單軸拉伸層合薄膜的單面上,藉由微凹版塗佈法將在四丁基鈦酸酯之四聚物(日本曹達股份有限公司製,商品名:TBT B-4)之石油英/正丁醇(3/1)溶液中添加對烷氧基金屬為0.5重量%之SiO2 微粒(日本耶阿洛吉魯股份有限公司製,R972,平均粒徑20nm),添加對烷氧基金屬為15莫耳%之γ-環氧丙氧基丙基三甲氧基矽烷之添加分散物塗佈之;於150℃乾燥2分鐘,形成厚度約80nm之膜(折射率1.75)。更於其上藉由濺鍍形成65nm之SnO2 層(折射率2.05)。最後將四乙基矽酸酯溶解於乙醇,將加入水及鹽酸水解而得之SiO2 溶膠塗佈,於100℃熱處理2分鐘形成凝膠膜(折射率1.45),即得單軸拉伸多層層合薄膜。所得薄膜之物性如表3所示。On the single side of the uniaxially stretched laminated film obtained in Comparative Example 1, a tetramer of tetrabutyl titanate (manufactured by Nippon Soda Co., Ltd., trade name: TBT B) was obtained by a micro gravure coating method. -4) Addition of 0.5% by weight of SiO 2 fine particles of alkoxy metal to a petroleum-in/n-butanol (3/1) solution (manufactured by Yayalujiru Co., Ltd., Japan, R972, average particle diameter: 20 nm) Adding an additive dispersion of γ-glycidoxypropyltrimethoxydecane having a 15% by mole of a metal alkoxide; drying at 150 ° C for 2 minutes to form a film having a thickness of about 80 nm (refractive index) 1.75). Further, a 65 nm SnO 2 layer (refractive index of 2.05) was formed by sputtering. Finally, tetraethyl phthalate was dissolved in ethanol, and SiO 2 sol obtained by hydrolysis of water and hydrochloric acid was applied, and heat-treated at 100 ° C for 2 minutes to form a gel film (refractive index of 1.45), that is, uniaxially stretched multilayer Laminated film. The physical properties of the obtained film are shown in Table 3.

圖1為本發明之單軸拉伸多層層合薄膜對光的偏光成份之波長的反射率之圖表的一例。Fig. 1 is a graph showing an example of a reflectance of a wavelength of a polarizing component of light in a uniaxially stretched multilayer laminated film of the present invention.

Claims (6)

一種單軸拉伸多層層合薄膜,其特徵為(A)將由具有正的應力光學係數之第一熱塑性樹脂所成且厚度為0.05~0.5 μm的第一層,及由與第一熱塑性樹脂相異之第二熱塑性樹脂所成之以DSC測定之結晶化尖峰存在於150~220℃之範圍且厚度為0.05~0.5 μm的第二層,交替合計501層以上而存在之單軸拉伸層合薄膜,及在該單軸拉伸層合薄膜之至少單面上,具有由射入側測定表面之反射率為3%以下之低反射率層;其中上述第一熱塑性樹脂係以全重複單位之95莫耳%以上之量含有2,6-萘二羧酸乙二醇酯(ethylene-2,6-naphthalene dicarboxylate)且熔點為260~270℃之聚酯,而上述第二熱塑性樹脂係相對於全重複單位由75~97莫耳%之2,6-萘二羧酸乙二醇酯與25~3莫耳%之對苯二甲酸乙二醇酯(ethylene terephthalate)及/或異苯二甲酸乙二醇酯(ethylene isophthalate)單位所成且熔點為210~255℃並且比上述第一熱塑性樹脂之熔點還低15~60℃之聚酯,(B)對含該單軸拉伸層合薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,平行的偏光成份之平均反射率在波長400~800nm的範圍為90%以上,且對含薄膜之拉伸方向與垂直於薄膜面之方向的兩方向之面,垂直的偏光成份之平均反射率在波長400~800nm的範圍為10%以下; 然後,(C)厚度變動率未滿5%且可使用於反射型偏光板。 A uniaxially stretched multilayer laminated film characterized by (A) a first layer of a first thermoplastic resin having a positive stress optical coefficient and having a thickness of 0.05 to 0.5 μm, and a phase of the first thermoplastic resin The second thermoplastic resin obtained by the second thermoplastic resin is formed by a DSC-measured crystallization peak in the range of 150 to 220 ° C and a thickness of 0.05 to 0.5 μm in the second layer, and 501 layers or more are alternately present in a uniaxially stretched laminate. a film having a low reflectance layer having a reflectance of 3% or less on the incident side of the uniaxially stretched laminated film; wherein the first thermoplastic resin is in a completely repeating unit 95% or more of the amount of ethylene containing 2,6-naphthalene dicarboxylate (ethylene-2,6-naphthalene dicarboxylate) and having a melting point of 260 to 270 ° C, and the second thermoplastic resin is relative to The total repeat unit is from 75 to 97 mol% of ethylene glycol 2,6-naphthalenedicarboxylate and 25 to 3 mol% of ethylene terephthalate and/or isophthalic acid. Ethylene isophthalate unit and melting point of 210-255 ° C and higher than the above first thermoplastic resin The polyester having a melting point lower than 15 to 60 ° C, (B) the average reflectance of the parallel polarizing component for the surface containing the uniaxially stretched laminated film and the direction perpendicular to the direction of the film surface The range of the wavelength range of 400 to 800 nm is 90% or more, and the average reflectance of the vertical polarization component is 10 in the range of 400 to 800 nm in the direction of the film-containing stretching direction and the direction perpendicular to the film surface. %the following; Then, the (C) thickness variation rate is less than 5% and can be used for the reflective polarizing plate. 如申請專利範圍第1項之單軸拉伸多層層合薄膜,其中對含薄膜之拉伸方向且垂直於薄膜面的方向之面,平行的偏光成份在波長400~800nm之範圍的最大反射率與最小反射率之差為10%以下。 The uniaxially stretched multi-layer laminated film according to the first aspect of the patent application, wherein the maximum reflectance of the parallel polarizing component in the range of wavelengths of 400 to 800 nm is applied to the surface containing the stretching direction of the film and perpendicular to the film surface. The difference from the minimum reflectance is 10% or less. 如申請專利範圍第1或2項之單軸拉伸多層層合薄膜,其中對含薄膜之拉伸方向且垂直於薄膜面的方向之面,垂直的偏光成份在波長400~800nm之範圍的最大反射率與最小反射率之差為10%以下。 The uniaxially stretched multilayer laminated film according to claim 1 or 2, wherein the vertical polarizing component is in the range of the wavelength range of 400 to 800 nm for the surface containing the stretching direction of the film and perpendicular to the film surface. The difference between the reflectance and the minimum reflectance is 10% or less. 一種液晶顯示用提升亮度薄膜,其特徵為由如申請專利範圍第1項之單軸拉伸多層層合薄膜所成。 A brightness enhancement film for liquid crystal display, which is characterized by being formed by a uniaxially stretched multilayer film as disclosed in claim 1 of the patent application. 一種單軸拉伸多層層合薄膜,其特徵為,(A)將由具有正的應力光學係數之第一熱塑性樹脂所成且厚度為0.05~0.5 μm的第一層,及由與第一熱塑性樹脂相異之第二熱塑性樹脂所成之以DSC測定之結晶化尖峰存在於150~220℃之範圍且厚度為0.05~0.5 μm的第二層,交替合計501層以上而存在之單軸拉伸層合薄膜,及在該單軸拉伸層合薄膜之至少單面上具有折射率1.1~1.45的低折射率層;其中上述第一熱塑性樹脂係以全重複單位之95莫耳%以上之量含有2,6-萘二羧酸乙二醇酯且熔點為260~270℃之聚酯,而上述第二熱塑性樹脂係相對於全重複單位由75~97莫耳%之2,6-萘二羧酸乙二醇酯與25~3莫耳%之對苯 二甲酸乙二醇酯及/或異苯二甲酸乙二醇酯單位所成且熔點為210~255℃並且比上述第一熱塑性樹脂之熔點還低15~60℃;(B)對含該單軸拉伸層合薄膜之拉伸方向且垂直於薄膜面的方向之面,平行的偏光成份之平均反射率在波長400~800nm的範圍為90%以上,對含薄膜之拉伸方向且垂直於薄膜面的方向之面,垂直的偏光成份之平均反射率在波長400~800nm的範圍為10%以下;然後,(C)厚度變動率未滿5%且可使用於反射型偏光板。 A uniaxially stretched multilayer laminated film characterized by (A) a first layer formed of a first thermoplastic resin having a positive stress optical coefficient and having a thickness of 0.05 to 0.5 μm, and a first thermoplastic resin A uniaxially stretched layer in which a crystallization peak having a thickness of 0.05 to 220 ° C and a thickness of 0.05 to 0.5 μm is present in a second thermoplastic resin having a difference of 501 layers or more And a low refractive index layer having a refractive index of 1.1 to 1.45 on at least one side of the uniaxially stretched laminated film; wherein the first thermoplastic resin is contained in an amount of 95% by mole or more of the total repeating unit 2,6-naphthalenedicarboxylate having a melting point of 260-270 ° C, and the second thermoplastic resin being 75-97 mol % of 2,6-naphthalenedicarboxylate relative to the total repeating unit Acid glycol ester with 25~3 mol% of para-benzene Ethylene glycol dicarboxylate and/or ethylene glycol isophthalate unit and having a melting point of 210-255 ° C and 15 to 60 ° C lower than the melting point of the first thermoplastic resin; (B) containing the single The axially stretched laminated film is oriented in a direction perpendicular to the direction of the film surface, and the average reflectance of the parallel polarizing components is 90% or more in the wavelength range of 400 to 800 nm, and is perpendicular to the stretching direction of the film. The average reflectance of the vertical polarizing component in the direction of the film surface is 10% or less in the wavelength range of 400 to 800 nm. Then, the (C) thickness variation rate is less than 5% and can be used for the reflective polarizing plate. 一種單軸拉伸多層層合薄膜的製造方法,其特徵為由以下步驟所成:由將熔點為260~270℃之第一熱塑性樹脂與比第一熱塑性樹脂之熔點低15~60℃且為210~255℃的熔點之第二熱塑性樹脂交替層合501層以上形成薄片的第一步驟,其中上述第一熱塑性樹脂係以全重複單位之95莫耳%以上之量含有2,6-萘二羧酸乙二醇酯且熔點為260~270℃之聚酯,而上述第二熱塑性樹脂係相對於全重複單位由75~97莫耳%之2,6-萘二羧酸乙二醇酯與25~3莫耳%之對苯二甲酸乙二醇酯及/或異苯二甲酸乙二醇酯單位所成且熔點為210~255℃並且比上述第一熱塑性樹脂之熔點還低15~60℃;將所得薄片在拉取方向或寬度方向之任一方向拉伸2~10倍的第二步驟;及將所得拉伸薄片在比第二熱塑性樹脂之熔點低10℃的 溫度與比第一熱塑性樹脂之熔點低15℃的溫度之間的溫度下進行熱處理之第三步驟。 A method for producing a uniaxially stretched multilayer laminated film, which is characterized in that: the first thermoplastic resin having a melting point of 260 to 270 ° C is 15 to 60 ° C lower than the melting point of the first thermoplastic resin and a first step of forming a sheet by alternately laminating 501 layers or more of a second thermoplastic resin having a melting point of 210 to 255 ° C, wherein the first thermoplastic resin contains 2,6-naphthalene in an amount of 95 mol% or more of the total repeating unit. a carboxylic acid glycol ester having a melting point of 260 to 270 ° C, and the second thermoplastic resin is from 75 to 97 mol % of ethylene glycol 2,6-naphthalenedicarboxylate relative to the total repeating unit. 25~3 mol% of ethylene terephthalate and/or ethylene isophthalate unit and melting point of 210-255 ° C and lower than the melting point of the first thermoplastic resin 15~60 °C; a second step of stretching the obtained sheet in any direction of the drawing direction or the width direction by 2 to 10 times; and the obtained stretched sheet is 10 ° C lower than the melting point of the second thermoplastic resin The third step of heat treatment is carried out at a temperature between the temperature and a temperature 15 ° C lower than the melting point of the first thermoplastic resin.
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JP4709746B2 (en) 2011-06-22
JPWO2005088363A1 (en) 2008-01-31

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